Tüm alıştırma soruları

2789 soru

Soru 2621Soru

An acute angle θ\theta satisfies the equation sin(θ)=2425\sin(\theta) = \frac{24}{25}. What is the value of 1cos(θ)tan(θ)\frac{1}{\cos(\theta)} - \tan(\theta)?

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Cevap: 17\frac{1}{7}

Cevap

The correct value of the expression is 17\frac{1}{7}.
The correct answer is 17\frac{1}{7}. Using the Pythagorean identity, we determine that cos(θ)=1sin2(θ)=725\cos(\theta) = \sqrt{1 - \sin^2(\theta)} = \frac{7}{25}. Using the definition of tangent, we find tan(θ)=sin(θ)cos(θ)=247\tan(\theta) = \frac{\sin(\theta)}{\cos(\theta)} = \frac{24}{7}. Substituting these values into the given expression yields 17/25247=257247=17\frac{1}{7/25} - \frac{24}{7} = \frac{25}{7} - \frac{24}{7} = \frac{1}{7}.

Adım Adım Çözüm

1
Find the value of cos(θ)\cos(\theta) using the Pythagorean identity sin2(θ)+cos2(θ)=1\sin^2(\theta) + \cos^2(\theta) = 1.
cos(θ)=725\cos(\theta) = \frac{7}{25}
Since θ\theta is an acute angle, cos(θ)=1sin2(θ)=1(2425)2=49625=725\cos(\theta) = \sqrt{1 - \sin^2(\theta)} = \sqrt{1 - \left(\frac{24}{25}\right)^2} = \sqrt{\frac{49}{625}} = \frac{7}{25}.
2
Find the value of tan(θ)\tan(\theta) using the definition tan(θ)=sin(θ)cos(θ)\tan(\theta) = \frac{\sin(\theta)}{\cos(\theta)}.
tan(θ)=247\tan(\theta) = \frac{24}{7}
Substituting the known values gives tan(θ)=24/257/25=247\tan(\theta) = \frac{24/25}{7/25} = \frac{24}{7}.
3
Substitute the values of cos(θ)\cos(\theta) and tan(θ)\tan(\theta) into the expression 1cos(θ)tan(θ)\frac{1}{\cos(\theta)} - \tan(\theta) and simplify.
17\frac{1}{7}
The expression becomes 17/25247=257247=17\frac{1}{7/25} - \frac{24}{7} = \frac{25}{7} - \frac{24}{7} = \frac{1}{7}.

Anahtar Kavram

Pythagorean identity and trigonometric ratio definitions in a right triangle
Soru 2622Soru

In the field of astrobiology, scientists study the light passing through the atmospheres of distant exoplanets to search for signs of life. The detection of key chemical biosignatures, such as seasonal variations in methane concentrations combined with high levels of oxygen, _______ the presence of active biological processes rather than abiotic chemical reactions.

Which choice completes the text so that it conforms to the conventions of Standard English?

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Cevap: indicates

Cevap

indicates
The subject of the sentence is the singular noun 'detection.' The intervening prepositional phrase 'of key chemical biosignatures' and the parenthetical example 'such as seasonal variations...' contain plural nouns ('biosignatures,' 'variations,' 'concentrations,' 'levels'), but they do not change the number of the subject. Therefore, the verb must be singular. The singular, present-tense verb 'indicates' correctly agrees with the singular subject 'detection.'

Adım Adım Çözüm

1
Identify the subject of the clause containing the blank.
The subject is the singular noun 'detection'.
The main verb must agree in number with the true subject of the clause.
2
Analyze the intervening words between the subject and the verb to avoid mistaking them for the subject.
The phrase 'of key chemical biosignatures, such as seasonal variations in methane concentrations combined with high levels of oxygen,' contains plural nouns ('biosignatures', 'variations', 'concentrations', 'levels') but functions as a modifier.
Nouns inside prepositional or parenthetical phrases do not affect the number of the main subject.
3
Select the verb form that is singular and fits the present-tense aspect of the passage.
The singular verb 'indicates' correctly completes the sentence, maintaining subject-verb agreement.
Singular subjects require singular verbs, and the general academic statement is best expressed in the simple present tense.

Anahtar Kavram

Subject-Verb Agreement
Soru 2623Soru

In the xyxy-plane, a circle with center (4,9)(4, 9) and radius 55 is defined by the equation (xh)2+(y9)2=25(x - h)^2 + (y - 9)^2 = 25, where hh is a positive constant. What is the value of hh?

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Cevap: 4

Cevap

The value of the constant hh is 44.
The standard equation of a circle with center (h,k)(h, k) and radius rr is (xh)2+(yk)2=r2(x - h)^2 + (y - k)^2 = r^2. Since the center is (4,9)(4, 9) and the radius is 55, the equation of the circle is (x4)2+(y9)2=52(x - 4)^2 + (y - 9)^2 = 5^2, which simplifies to (x4)2+(y9)2=25(x - 4)^2 + (y - 9)^2 = 25. Comparing this to the given equation (xh)2+(y9)2=25(x - h)^2 + (y - 9)^2 = 25, we see that the constant hh corresponds to the xx-coordinate of the center, which is 44.

Adım Adım Çözüm

1
Identify the standard equation of a circle.
(xh)2+(yk)2=r2(x - h)^2 + (y - k)^2 = r^2
This formula represents a circle with center (h,k)(h, k) and radius rr in the coordinate plane.
2
Substitute the given center coordinates into the standard equation.
For center (4,9)(4, 9), the equation is (x4)2+(y9)2=r2(x - 4)^2 + (y - 9)^2 = r^2.
The coordinates of the center are mapped directly to hh and kk in the standard form.
3
Compare the equation template to find the value of hh.
The equation (x4)2+(y9)2=25(x - 4)^2 + (y - 9)^2 = 25 matches the format (xh)2+(y9)2=25(x - h)^2 + (y - 9)^2 = 25, indicating that h=4h = 4.
Equating the terms in both equations allows us to identify the value of the positive constant hh.

Anahtar Kavram

Extracting coordinates of the center from the standard form equation of a circle.
Soru 2624Soru

Astronomers analyzing the atmospheres of exoplanets have found that some hot Jupiters exhibit weather patterns far more extreme than those seen in our solar system. _______, on the exoplanet HD 189733b, winds can reach speeds of over 5,000 miles per hour, carrying clouds of silicate particles that cause it to rain liquid glass.

Which choice completes the passage with the most logical transition?

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Cevap: For example

Cevap

For example
The first sentence makes a general assertion about extreme weather on some hot Jupiters. The second sentence supports and details this assertion by describing the specific weather conditions on the exoplanet HD 189733b. The transition 'For example' is the only option that correctly establishes this exemplification relationship.

Adım Adım Çözüm

1
Analyze the relationship between the two sentences in the passage.
The first sentence introduces a general claim that some hot Jupiters have weather patterns far more extreme than those in our solar system. The second sentence presents a specific exoplanet, HD 189733b, and describes its extreme weather conditions.
Identifying the relationship allows us to determine what category of transition word is needed.
2
Classify the connection as elaboration/exemplification.
Since the second sentence illustrates the general claim of the first sentence with a specific case, the transition must signal exemplification.
An exemplification transition is necessary to logically connect a general statement to a specific instance.
3
Evaluate the choices against this classification.
The transition 'For example' matches this relationship. Other choices introduce incorrect relationships such as cause-and-effect, contrast, or chronological sequence.
Selecting the option that matches the exemplification relationship completes the passage logically.

Anahtar Kavram

Transitions: Elaboration and Exemplification
Soru 2625Soru

A dermatologist at a medical clinic wants to estimate the proportion of residents in a city who experience seasonal dry skin. The dermatologist surveys a random sample of 150 patients who visited the clinic in December and finds that 90 of them (60%) reported experiencing seasonal dry skin. Which of the following is the most appropriate conclusion based on this study?

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Cevap: No reliable conclusion can be drawn about the proportion of all residents in the city who experience seasonal dry skin because the sample is not representative of the city's population.

Cevap

No reliable conclusion can be drawn about the proportion of all residents in the city who experience seasonal dry skin because the sample is not representative of the city's population.
The correct conclusion is that no reliable conclusion can be drawn about all residents of the city. For a sample's findings to be generalized to a larger population, the sample must be randomly selected from that population. In this study, the sample is composed of patients at a dermatology clinic, who are more likely to have skin concerns, and the study was done in December, when dry skin is seasonally more common. Therefore, the sample is not representative of the city's general population, and we cannot generalize the 60% statistic to the entire city.

Adım Adım Çözüm

1
Identify the population of interest and the sample group.
The population of interest is all residents of the city. The sample group is 150 patients visiting a dermatology clinic in December.
Understanding the relationship between the sample and the population is necessary to determine if generalization is valid.
2
Evaluate whether the sample is representative of the population of interest.
The sample is not representative because dermatology patients are more likely to have skin issues than the average resident, and December is a winter month when dry skin is more common.
A sample must be randomly selected and representative of the target population to allow for valid generalization.
3
Select the conclusion that reflects the limitation of the sample.
The only appropriate conclusion is that no reliable conclusion can be drawn about the general city population from this biased sample.
Since the sample is biased and non-representative, generalizing the results would lead to an incorrect conclusion about the population of all city residents.

Anahtar Kavram

Generalizability of study results based on sample selection and representativeness.
Soru 2626Soru

For an acute angle θ\theta, the expression sin(θ)+cos(θ)sec(θ)+csc(θ)\frac{\sin(\theta) + \cos(\theta)}{\sec(\theta) + \csc(\theta)} is equal to kk. If tan(θ)=3\tan(\theta) = 3, what is the value of kk?

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Cevap: 310\frac{3}{10}

Cevap

The correct answer is three-tenths, or 3/10.
The correct answer is 310\frac{3}{10}. By rewriting the denominator using reciprocal identities, we have sec(θ)+csc(θ)=1cos(θ)+1sin(θ)=sin(θ)+cos(θ)sin(θ)cos(θ)\sec(\theta) + \csc(\theta) = \frac{1}{\cos(\theta)} + \frac{1}{\sin(\theta)} = \frac{\sin(\theta) + \cos(\theta)}{\sin(\theta)\cos(\theta)}. Dividing the numerator by this expression simplifies the entire fraction to sin(θ)cos(θ)\sin(\theta)\cos(\theta). Using the reference right triangle for tan(θ)=3\tan(\theta) = 3, we find that sin(θ)=310\sin(\theta) = \frac{3}{\sqrt{10}} and cos(θ)=110\cos(\theta) = \frac{1}{\sqrt{10}}, which gives a product of 310\frac{3}{10}.

Adım Adım Çözüm

1
Rewrite the terms in the denominator using their reciprocal definitions.
sec(θ)=1cos(θ)\sec(\theta) = \frac{1}{\cos(\theta)} and csc(θ)=1sin(θ)\csc(\theta) = \frac{1}{\sin(\theta)}, so the expression becomes sin(θ)+cos(θ)1cos(θ)+1sin(θ)\frac{\sin(\theta) + \cos(\theta)}{\frac{1}{\cos(\theta)} + \frac{1}{\sin(\theta)}}.
Expressing secant and cosecant in terms of sine and cosine allows for the simplification of the complex fraction.
2
Combine the terms in the denominator by finding a common denominator.
1cos(θ)+1sin(θ)=sin(θ)+cos(θ)sin(θ)cos(θ)\frac{1}{\cos(\theta)} + \frac{1}{\sin(\theta)} = \frac{\sin(\theta) + \cos(\theta)}{\sin(\theta)\cos(\theta)}.
Finding a common denominator simplifies the addition of the fractional terms.
3
Divide the numerator by the simplified denominator.
sin(θ)+cos(θ)sin(θ)+cos(θ)sin(θ)cos(θ)=sin(θ)cos(θ)\frac{\sin(\theta) + \cos(\theta)}{\frac{\sin(\theta) + \cos(\theta)}{\sin(\theta)\cos(\theta)}} = \sin(\theta)\cos(\theta).
Since θ\theta is an acute angle, the sum sin(θ)+cos(θ)\sin(\theta) + \cos(\theta) is non-zero, allowing it to be canceled from both the numerator and the denominator.
4
Find the values of sin(θ)\sin(\theta) and cos(θ)\cos(\theta) using the given relation tan(θ)=3\tan(\theta) = 3.
Construct a right triangle where the opposite side to angle θ\theta is 33 and the adjacent side is 11. The hypotenuse is 32+12=10\sqrt{3^2 + 1^2} = \sqrt{10}. Therefore, sin(θ)=310\sin(\theta) = \frac{3}{\sqrt{10}} and cos(θ)=110\cos(\theta) = \frac{1}{\sqrt{10}}.
Using a reference right triangle is a direct way to find the values of other trigonometric functions from a known tangent value.
5
Multiply the values of sin(θ)\sin(\theta) and cos(θ)\cos(\theta) to find the value of kk.
k=sin(θ)cos(θ)=(310)(110)=310k = \sin(\theta)\cos(\theta) = \left(\frac{3}{\sqrt{10}}\right)\left(\frac{1}{\sqrt{10}}\right) = \frac{3}{10}.
This yields the final numerical value of the expression.

Anahtar Kavram

Simplification of trigonometric expressions using reciprocal identities and finding trigonometric ratios from a given tangent ratio.
Soru 2627Soru

If sin(2x+10)=cos(3x5)\sin(2x + 10)^\circ = \cos(3x - 5)^\circ, where the measures of both angles are in degrees and are acute, what is the value of xx?

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Cevap: 17

Cevap

17
According to the co-function identities of trigonometry, the sine of an acute angle is equal to the cosine of its complementary angle. Therefore, if sin(2x+10)=cos(3x5)\sin(2x + 10)^\circ = \cos(3x - 5)^\circ, the sum of the two angles must be 9090^\circ. This gives the equation (2x+10)+(3x5)=90(2x + 10) + (3x - 5) = 90. Simplifying the equation yields 5x+5=905x + 5 = 90. Subtracting 5 from both sides gives 5x=855x = 85, and dividing by 5 yields x=17x = 17.

Adım Adım Çözüm

1
Relate the sine and cosine functions using the co-function identity.
Since sin(A)=cos(B)\sin(A) = \cos(B) for acute angles, the angles must be complementary, so A+B=90A + B = 90^\circ.
The co-function identity states that the sine of an angle is equal to the cosine of its complement.
2
Set up the algebraic equation using the given angle expressions.
(2x+10)+(3x5)=90(2x + 10) + (3x - 5) = 90
This expresses the condition that the sum of the two acute angles is equal to 9090^\circ.
3
Solve the equation for xx.
5x+5=90    5x=85    x=175x + 5 = 90 \implies 5x = 85 \implies x = 17
Combine like terms and isolate xx by performing basic arithmetic operations.

Anahtar Kavram

Co-function identities relate trigonometric functions of complementary angles, specifically sin(θ)=cos(90θ)\sin(\theta) = \cos(90^\circ - \theta).
Soru 2628Soru

Zooarchaeologists studying ancient pastoral societies often analyze stable isotope ratios in animal teeth to reconstruct seasonal migration patterns. ______ by measuring the strontium isotopes in sheep molars, researchers can determine whether the herds were grazed in local valleys or driven to distant highland pastures during the summer months.

Which choice completes the passage with the most logical transition?

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Cevap: In particular

Cevap

In particular
The sentence before the transition discusses the general practice of analyzing stable isotope ratios in animal teeth to reconstruct migration patterns. The sentence after the transition describes a specific application of this practice: measuring strontium isotopes in sheep molars. The transition 'In particular' is correct because it introduces a specific, illustrative example that elaborates on the general statement.

Adım Adım Çözüm

1
Analyze the relationship between the two sentences separated by the blank.
The first sentence makes a general statement about analyzing stable isotope ratios in animal teeth. The second sentence provides a specific example of this methodology (strontium isotopes in sheep molars).
Identifying the logical flow is necessary to determine the appropriate category of transition word.
2
Identify the category of transition needed.
Since the second sentence provides a specific example of the general statement in the first sentence, an elaboration or exemplification transition is required.
This narrows down the choices to words or phrases that introduce specific instances or detail.
3
Evaluate the choices to find the transition that fits this category.
'In particular' functions as an elaboration/exemplification transition, while the other choices represent chronological, cause-effect, or contrast relationships.
Selecting the option that matches the identified category ensures a logical transition.

Anahtar Kavram

Transitions: Elaboration and Exemplification
Tahmini Süre:1m 0s
Soru 2629Soru

In the diagram shown, point DD lies on side ABAB of triangle ABCABC, and point EE lies on side ACAC. The lengths of the segments are AB=20AB = 20, AC=16AC = 16, AD=8AD = 8, and AE=10AE = 10. If the area of quadrilateral BCEDBCED is 5454, what is the area of triangle ADEADE?

(Note: Figure not drawn to scale.)

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Cevap: 18

Cevap

18
Triangles ADE and ACB share angle A. The ratios of the adjacent sides of angle A are AD/AC = 8/16 = 1/2 and AE/AB = 10/20 = 1/2. By the Side-Angle-Side (SAS) similarity theorem, triangle ADE is similar to triangle ACB. The ratio of their areas is equal to the square of their similarity ratio: (1/2)^2 = 1/4. Therefore, the area of triangle ACB is 4 times the area of triangle ADE. The area of quadrilateral BCED is the difference between the area of triangle ACB and the area of triangle ADE, which is 4 * Area(ADE) - Area(ADE) = 3 * Area(ADE). Since the area of quadrilateral BCED is 54, we have 3 * Area(ADE) = 54, which simplifies to Area(ADE) = 18.

Adım Adım Çözüm

1
Calculate side ratios to establish similarity.
The ratio of AD to AC is 8/16 = 1/2, and the ratio of AE to AB is 10/20 = 1/2.
Checking if the corresponding sides surrounding the shared angle are in the same proportion.
2
Apply the Side-Angle-Side (SAS) similarity theorem.
Triangle ADE is similar to triangle ACB (triangle ADE ~ triangle ACB), where vertex A corresponds to A, D corresponds to C, and E corresponds to B.
Since the ratio of two pairs of corresponding sides is equal and their included angle is congruent, the triangles are similar.
3
Determine the area ratio based on the similarity scale factor.
The ratio of the area of triangle ADE to the area of triangle ACB is (1/2)^2 = 1/4.
The ratio of the areas of two similar figures is equal to the square of their similarity ratio.
4
Relate the area of the quadrilateral to the area of the smaller triangle.
Area(BCED) = Area(ACB) - Area(ADE) = 4 * Area(ADE) - Area(ADE) = 3 * Area(ADE).
The area of the quadrilateral is the difference between the areas of the larger and smaller triangles.
5
Solve for the area of triangle ADE.
Area(ADE) = 54 / 3 = 18.
Dividing the given area of the quadrilateral by 3 yields the area of the smaller triangle.

Anahtar Kavram

SAS Triangle Similarity and the Area Ratios of Similar Triangles
Tahmini Süre:2m 30s
Soru 2630Soru

The quadratic function ff is defined by f(x)=(x4)(x10)f(x) = (x - 4)(x - 10). In the xyxy-plane, the graph of function gg is obtained by translating the graph of ff horizontally so that the vertex of the graph of gg lies on the yy-axis. Which of the following equations defines the function gg?

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Cevap: g(x)=x29g(x) = x^2 - 9

Cevap

The correct equation is g(x)=x29g(x) = x^2 - 9.
The x-coordinate of the vertex of the graph of f(x)=(x4)(x10)f(x) = (x - 4)(x - 10) is the average of its x-intercepts: 4+102=7\frac{4 + 10}{2} = 7. For the vertex of the graph of gg to lie on the y-axis, the x-coordinate of the new vertex must be 0. This requires translating the graph of ff to the left by 7 units, which corresponds to the transformation g(x)=f(x+7)g(x) = f(x + 7). Substituting x+7x + 7 for xx in f(x)f(x) gives g(x)=((x+7)4)((x+7)10)=(x+3)(x3)=x29g(x) = ((x + 7) - 4)((x + 7) - 10) = (x + 3)(x - 3) = x^2 - 9.

Adım Adım Çözüm

1
Identify the x-intercepts of the function f(x)=(x4)(x10)f(x) = (x - 4)(x - 10).
The x-intercepts are x=4x = 4 and x=10x = 10.
The x-intercepts occur where the function equals zero, which are the roots of the factors.
2
Find the x-coordinate of the vertex of the graph of ff.
The x-coordinate of the vertex is x=7x = 7.
The axis of symmetry (and thus the x-coordinate of the vertex) is the average of the x-intercepts: 4+102=7\frac{4 + 10}{2} = 7.
3
Determine the translation needed to place the vertex on the y-axis.
Translate the graph to the left by 7 units.
The y-axis corresponds to x=0x = 0. To move the vertex from x=7x = 7 to x=0x = 0, the graph must be shifted 7 units to the left.
4
Apply the horizontal translation to find the equation for g(x)g(x).
g(x)=(x+3)(x3)=x29g(x) = (x + 3)(x - 3) = x^2 - 9.
A horizontal translation of 7 units to the left is represented by g(x)=f(x+7)g(x) = f(x + 7). Substituting x+7x + 7 for xx in the equation for f(x)f(x) gives ((x+7)4)((x+7)10)=(x+3)(x3)=x29((x + 7) - 4)((x + 7) - 10) = (x + 3)(x - 3) = x^2 - 9.

Anahtar Kavram

Identifying the vertex of a quadratic function from its factored form and applying horizontal translation rules.
Soru 2631Soru

While preparing a presentation on Anglo-Saxon history, a student took the following notes:
- The Sutton Hoo helmet is an Anglo-Saxon artifact discovered in Suffolk, England, in 1939.
- It was found in a ship-grave believed to be the burial site of King Rædwald of East Anglia.
- The helmet was reconstructed from hundreds of corroded iron fragments.
- The reconstruction was carried out by conservators at the British Museum.
- Its design features a decorative face mask that resembles a flying dragon.

The student wants to emphasize the location where the helmet was discovered and the institution that reconstructed it. Which choice most effectively uses information from the given notes to accomplish this goal?

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Cevap: The Sutton Hoo helmet was discovered in Suffolk, England, in 1939 and was later reconstructed by conservators at the British Museum.

Cevap

The Sutton Hoo helmet was discovered in Suffolk, England, in 1939 and was later reconstructed by conservators at the British Museum.
The correct option successfully addresses the student's goal by stating that the helmet was discovered in Suffolk, England (the location of discovery) and was reconstructed by conservators at the British Museum (the institution that reconstructed it).

Adım Adım Çözüm

1
Analyze the prompt to identify the specific goal and required details.
The goal is to emphasize two specific pieces of information: the location where the helmet was discovered (Suffolk, England) and the institution that reconstructed it (the British Museum).
Understanding the precise criteria of the prompt is necessary to evaluate the options.
2
Evaluate the options against the identified criteria.
The option stating the helmet was discovered in Suffolk, England, and reconstructed at the British Museum contains both details. Other options either omit one of the required details or introduce factual inaccuracies not supported by the notes.
This step eliminates incorrect options that either miss the required details or present incorrect information.

Anahtar Kavram

Rhetorical Synthesis: Emphasizing Specific Details
Soru 2632Soru

An educational organization wants to estimate the number of high school seniors in a school district who plan to major in a STEM field. A random sample of 320320 high school seniors in the district was surveyed, and 35%35\% of the surveyed students reported that they plan to major in a STEM field. The survey has an associated margin of error of 4%4\%. There are 4,5004,500 high school seniors in the school district. Based on these results, what is the maximum estimated number of high school seniors in the district who plan to major in a STEM field?

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Cevap: 1755

Cevap

1755
The survey estimate for the proportion of students who plan to major in a STEM field is 35%35\% with a margin of error of 4%4\%. This means the true proportion is estimated to be between 35%4%=31%35\% - 4\% = 31\% and 35%+4%=39%35\% + 4\% = 39\%. To find the maximum estimated number of students in the population of 4,5004,500, we use the maximum estimated proportion of 39%39\% (or 0.390.39). Multiplying 0.390.39 by 4,5004,500 yields 1,7551,755.

Adım Adım Çözüm

1
Calculate the maximum estimated percentage of students by adding the margin of error to the sample percentage.
39%39\% (or 0.390.39)
The margin of error gives the range of values above and below the sample estimate that represents the true population proportion. The maximum value of this range is found by adding the margin of error.
2
Multiply the maximum estimated proportion by the total number of high school seniors in the district.
1,755
To generalize the sample results to the entire population of 4,5004,500 seniors, multiply the maximum proportion by the total population size.

Anahtar Kavram

Estimating population parameters using sample proportions and margin of error
Soru 2633Soru

A juice mixture is made by combining orange concentrate and water in a ratio of 22 to 55 by volume. To make a large batch of this mixture, a worker uses a total of 3535 liters of water. If the worker wants to dilute the mixture so that the new ratio of orange concentrate to water is 11 to 44 by volume, how many additional liters of water must be added?

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Cevap: 21

Cevap

21
The correct answer is 21. First, we find the volume of orange concentrate in the initial mixture. The ratio of orange concentrate to water is 2 to 5, and the volume of water is 35 liters. Setting up the proportion 25=concentrate35\frac{2}{5} = \frac{\text{concentrate}}{35} gives a concentrate volume of 14 liters. When the mixture is diluted, the amount of orange concentrate remains 14 liters, but the ratio of concentrate to water becomes 1 to 4. Setting up the new proportion 14=14new water\frac{1}{4} = \frac{14}{\text{new water}} gives a new water volume of 56 liters. The additional water required is the difference between the final and initial water volumes, which is 5635=2156 - 35 = 21 liters.

Adım Adım Çözüm

1
Determine the volume of orange concentrate in the initial mixture.
The initial ratio of orange concentrate to water is 2:52:5. Since the mixture contains 3535 liters of water, the volume of orange concentrate, xx, can be found using the proportion 25=x35\frac{2}{5} = \frac{x}{35}. Solving for xx gives x=2×355=14x = \frac{2 \times 35}{5} = 14 liters.
The amount of orange concentrate must be determined because it remains constant during dilution.
2
Calculate the total volume of water needed for the diluted mixture.
In the diluted mixture, the ratio of orange concentrate to water is 1:41:4. Since the amount of orange concentrate is still 1414 liters, the new volume of water, yy, can be found using the proportion 14=14y\frac{1}{4} = \frac{14}{y}. Solving for yy gives y=14×4=56y = 14 \times 4 = 56 liters.
The final volume of water is required to determine the additional amount of water that needs to be added.
3
Find the additional volume of water that must be added.
Subtract the initial volume of water from the final volume of water: 5635=2156 - 35 = 21 liters.
Subtracting the starting amount of water gives the volume of new water needed to achieve the target ratio.

Anahtar Kavram

Using proportions to solve multi-step mixture and dilution problems.
Soru 2634Soru

In glaciology, cryophilic algae thrive on glacier surfaces during melting seasons. To protect themselves from intense ultraviolet radiation, these algae produce dark-colored pigments. However, these pigments also reduce the albedo—or reflectivity—of the ice surface, causing it to absorb more solar radiation. Researchers investigating the Greenland Ice Sheet observed that areas with high densities of cryophilic algae experienced melting rates that significantly exceeded predictions based solely on regional atmospheric temperatures. Since regional air temperatures remained stable, this discrepancy suggests that ______

Which choice most logically completes the text?

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Cevap: the presence of cryophilic algae directly accelerated the ice melt by increasing the absorption of solar radiation.

Cevap

the presence of cryophilic algae directly accelerated the ice melt by increasing the absorption of solar radiation.
The correct answer is correct because the passage directly links the algae's dark pigments to decreased reflectivity and increased solar absorption, which explains the accelerated melting rate that occurred independent of atmospheric temperature changes.

Adım Adım Çözüm

1
Identify the core premises in the passage.
The passage establishes that cryophilic algae produce dark pigments that decrease reflectivity (albedo) and increase solar radiation absorption. High-density algae areas melted faster than predicted by temperature alone, while regional temperatures remained stable.
Establishing the facts and relationships presented in the text is necessary to draw a logical conclusion.
2
Analyze the discrepancy in the melting rate.
The melting rate exceeded predictions based on temperature, but temperatures were stable, pointing to a non-temperature factor.
This isolates the albedo-reduction effect of the dark pigments as the variable driving the accelerated melting.
3
Formulate a conclusion that ties the premises together without introducing outside assumptions.
The algae's presence and pigments directly accelerated the ice melt by increasing the absorption of solar radiation.
This is the only direct, non-speculative inference supported by the premises.

Anahtar Kavram

Logical Inferences
Tahmini Süre:1m 30s
Soru 2635Soru

In the xyxy-plane, an angle θ\theta is in standard position. The terminal ray of θ\theta is rotated counterclockwise by 7π6\frac{7\pi}{6} radians, and then rotated clockwise by 135135^\circ. If the terminal ray of the resulting angle lies on the line y=xy = -x in the fourth quadrant, and the original angle θ\theta has a measure of dd degrees, where 0d<3600 \leq d < 360, what is the value of dd?

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Cevap: 240

Cevap

The value of dd is 240.
A terminal ray in the fourth quadrant lying on the line y=xy = -x forms a 315315^\circ angle in standard position. The first rotation is counterclockwise by 7π6\frac{7\pi}{6} radians, which is equivalent to 7π6×180π=210\frac{7\pi}{6} \times \frac{180^\circ}{\pi} = 210^\circ. The second rotation is clockwise by 135135^\circ, representing a decrease of 135135^\circ. Therefore, the total transformation is θ+210135=315\theta + 210^\circ - 135^\circ = 315^\circ. Solving for θ\theta gives θ+75=315\theta + 75^\circ = 315^\circ, which simplifies to θ=240\theta = 240^\circ. Since 240240^\circ lies in the interval [0,360)[0, 360), the value of dd is 240.

Adım Adım Çözüm

1
Determine the angle in standard position for a terminal ray on the line y=xy = -x in the fourth quadrant.
The terminal ray corresponds to an angle of 315315^\circ (or any angle coterminal with it).
The line y=xy = -x in the fourth quadrant makes an angle of 4545^\circ below the positive xx-axis, which corresponds to 36045=315360^\circ - 45^\circ = 315^\circ in standard position.
2
Convert the counterclockwise rotation from radians to degrees.
7π6 radians=210\frac{7\pi}{6} \text{ radians} = 210^\circ.
To convert radians to degrees, multiply the angle in radians by 180π\frac{180^\circ}{\pi}.
3
Express the rotations mathematically and set up the equation for θ\theta.
θ+210135=315+360n\theta + 210^\circ - 135^\circ = 315^\circ + 360^\circ n (where nn is an integer).
In standard position, counterclockwise rotations represent positive changes in angle measure, whereas clockwise rotations represent negative changes in angle measure.
4
Solve for θ\theta and apply the domain restriction 0d<3600 \leq d < 360.
θ=240\theta = 240^\circ, so d=240d = 240.
Simplifying the equation gives θ+75=315\theta + 75^\circ = 315^\circ, which yields θ=240\theta = 240^\circ when n=0n=0.

Anahtar Kavram

Converting angles from radians to degrees, understanding the direction of rotation, and determining standard position angles on the coordinate plane.
Soru 2636Soru

A consumer electronics reviewer is tracking the resale value of two different smartphone models. At the time of purchase (t=0t = 0 years), Smartphone A and Smartphone B each have a retail value of 1,0001,000 dollars. The value of Smartphone A decreases by 10%10\% of its value from the previous year each year. The value of Smartphone B decreases by a constant amount of 100100 dollars each year. What is the difference, in dollars, between the values of the two smartphones 33 years after they were purchased?

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Cevap: 29

Cevap

The difference between the values of the two smartphones is 29 dollars.
The correct answer is the option showing a difference of 2929 dollars. To solve this, we model each smartphone's resale value over time. Smartphone A experiences exponential decay with a decay factor of 0.900.90. Its value after 33 years is 1,000(0.90)3=7291,000(0.90)^3 = 729 dollars. Smartphone B experiences linear decay with a constant rate of decrease of 100100 dollars per year. Its value after 33 years is 1,000100(3)=7001,000 - 100(3) = 700 dollars. The difference between these two values is 729700=29729 - 700 = 29 dollars.

Adım Adım Çözüm

1
Find the value of Smartphone A at t=3t = 3 years.
The resale value of Smartphone A is 1,000(10.10)3=1,000(0.90)3=1,000(0.729)=7291,000(1 - 0.10)^3 = 1,000(0.90)^3 = 1,000(0.729) = 729 dollars.
Smartphone A decreases by a constant percentage of 10%10\% each year, which represents exponential decay.
2
Find the value of Smartphone B at t=3t = 3 years.
The resale value of Smartphone B is 1,000100(3)=1,000300=7001,000 - 100(3) = 1,000 - 300 = 700 dollars.
Smartphone B decreases by a constant absolute amount of 100100 dollars each year, which represents linear decay.
3
Calculate the difference between the two values at t=3t = 3 years.
729700=29729 - 700 = 29 dollars.
Subtract the smaller value from the larger value to find the positive difference.

Anahtar Kavram

Linear and Exponential Growth and Decay
Soru 2637Soru

The equation of a circle in the xyxy-plane is (x8)2+(y+1)2=81(x - 8)^2 + (y + 1)^2 = 81. What are the coordinates of the center of the circle?

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Cevap: (8,1)(8, -1)

Cevap

The center of the circle is (8,1)(8, -1)
The standard form of the equation of a circle in the xyxy-plane is (xh)2+(yk)2=r2(x - h)^2 + (y - k)^2 = r^2, where the center is (h,k)(h, k). In the given equation (x8)2+(y+1)2=81(x - 8)^2 + (y + 1)^2 = 81, comparing the terms to the standard form gives h=8h = 8 and k=1k = -1. Thus, the center of the circle is (8,1)(8, -1).

Adım Adım Çözüm

1
State the standard form of a circle's equation
The standard equation of a circle with center (h,k)(h, k) and radius rr is (xh)2+(yk)2=r2(x - h)^2 + (y - k)^2 = r^2.
This establishes the template to match the given equation against.
2
Rewrite the given equation to match the standard form exactly
The given equation (x8)2+(y+1)2=81(x - 8)^2 + (y + 1)^2 = 81 can be rewritten as (x8)2+(y(1))2=92(x - 8)^2 + (y - (-1))^2 = 9^2.
Rewriting helps clearly identify the signs of hh and kk since the standard form uses subtraction: (xh)(x - h) and (yk)(y - k).
3
Extract the center coordinates (h,k)(h, k)
h=8h = 8 and k=1k = -1, giving the coordinates (8,1)(8, -1).
By matching the rewritten equation to the standard form, we find the specific values of hh and kk that define the circle's center.

Anahtar Kavram

Identifying the center of a circle from its standard equation form
Tahmini Süre:45s
Soru 2638Soru

In the xyxy-plane, the graph of the polynomial function gg, defined by g(x)=3(xk)(x+2)2g(x) = 3(x - k)(x + 2)^2, has a yy-intercept at (0,24)(0, -24), where kk is a constant. What is the value of kk?

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Cevap: 2

Cevap

The correct answer is 2.
Evaluating the function at x=0x = 0 yields g(0)=3(k)(2)2=12kg(0) = 3(-k)(2)^2 = -12k. Setting this equal to the given yy-intercept value of 24-24 gives 12k=24-12k = -24. Solving for kk gives k=2k = 2.

Adım Adım Çözüm

1
Determine the value of the function at the yy-intercept
g(0)=24g(0) = -24
The yy-intercept of a graph in the xyxy-plane is the point where x=0x = 0. Since the yy-intercept is (0,24)(0, -24), the function value when x=0x = 0 must be 24-24.
2
Substitute x=0x = 0 into the function definition
g(0)=3(0k)(0+2)2g(0) = 3(0 - k)(0 + 2)^2
To evaluate the expression at x=0x = 0, we substitute 00 for every instance of xx in the equation.
3
Simplify the algebraic expression
g(0)=12kg(0) = -12k
Simplifying the terms: (0+2)2=4(0+2)^2 = 4, and 3(0k)=3k3(0-k) = -3k. Multiplying these gives 3k×4=12k-3k \times 4 = -12k.
4
Solve for the constant kk
k=2k = 2
Equating the simplified expression to the known yy-value at the intercept gives 12k=24-12k = -24. Dividing both sides by 12-12 yields k=2k = 2.

Anahtar Kavram

Using the y-intercept of a polynomial function to solve for an unknown constant coefficient.
Soru 2639Soru

In right triangle DEFDEF, the measure of angle FF is 9090^\circ. If cos(D)=35\cos(D) = \frac{3}{5}, what is the value of sin(E)tan(D)\sin(E) - \tan(D)?

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Cevap: 1115-\frac{11}{15}

Cevap

1115-\frac{11}{15}
To find the value of sin(E)tan(D)\sin(E) - \tan(D), we first determine the trigonometric ratios for triangle DEFDEF. Since DD and EE are the two acute angles in right triangle DEFDEF with the right angle at FF, the angles are complementary, which means sin(E)=cos(D)=35\sin(E) = \cos(D) = \frac{3}{5}. Next, using the definition of cosine, cos(D)=adjacenthypotenuse=35\cos(D) = \frac{\text{adjacent}}{\text{hypotenuse}} = \frac{3}{5}. By the Pythagorean theorem, the length of the opposite side to angle DD is 5232=4\sqrt{5^2 - 3^2} = 4. Therefore, tan(D)=oppositeadjacent=43\tan(D) = \frac{\text{opposite}}{\text{adjacent}} = \frac{4}{3}. Substituting these values into the expression gives sin(E)tan(D)=3543=92015=1115\sin(E) - \tan(D) = \frac{3}{5} - \frac{4}{3} = \frac{9 - 20}{15} = -\frac{11}{15}.

Adım Adım Çözüm

1
Identify the relationship between the acute angles in right triangle DEFDEF.
Since angle FF is 9090^\circ, angles DD and EE are complementary, meaning D+E=90D + E = 90^\circ. By the co-function identity, sin(E)=cos(D)\sin(E) = \cos(D).
This allows us to determine sin(E)\sin(E) directly from the given value of cos(D)\cos(D) without finding angle measures.
2
Determine the value of sin(E)\sin(E) and find the side lengths of triangle DEFDEF.
sin(E)=cos(D)=35\sin(E) = \cos(D) = \frac{3}{5}. Using the ratio cos(D)=adjacenthypotenuse=35\cos(D) = \frac{\text{adjacent}}{\text{hypotenuse}} = \frac{3}{5}, we let the adjacent side DF=3DF = 3 and the hypotenuse DE=5DE = 5. By the Pythagorean theorem, the opposite side is EF=5232=4EF = \sqrt{5^2 - 3^2} = 4.
These side lengths are necessary to calculate the value of tan(D)\tan(D).
3
Calculate the value of tan(D)\tan(D) and evaluate the given expression.
tan(D)=oppositeadjacent=EFDF=43\tan(D) = \frac{\text{opposite}}{\text{adjacent}} = \frac{EF}{DF} = \frac{4}{3}. Evaluating the expression: sin(E)tan(D)=3543=92015=1115\sin(E) - \tan(D) = \frac{3}{5} - \frac{4}{3} = \frac{9 - 20}{15} = -\frac{11}{15}.
This completes the subtraction to find the final value of the expression.

Anahtar Kavram

Trigonometric ratios in right triangles and co-function identities of complementary angles.

Alternatif Yöntem

Instead of using the co-function identity, one can draw a right triangle DEFDEF with adjacent side DF=3DF = 3 and hypotenuse DE=5DE = 5. Using the Pythagorean theorem, the opposite side EF=4EF = 4. From the triangle, sin(E)=DFDE=35\sin(E) = \frac{DF}{DE} = \frac{3}{5} and tan(D)=EFDF=43\tan(D) = \frac{EF}{DF} = \frac{4}{3}. Evaluating the expression gives 3543=1115\frac{3}{5} - \frac{4}{3} = -\frac{11}{15}.
Tahmini Süre:1m 30s
Soru 2640Soru

Which word completes the text with the most logical and precise word?

Aşağıdaki boşlukları doldurun

In conservation biology, the concept of ecological corridors has gained prominence as a means to connect fragmented habitats. However, some researchers caution that these corridors can also facilitate the spread of invasive species and diseases. Consequently, the establishment of corridors is not a guaranteed remedy but rather a complex strategy that requires planning to balance potential ecological benefits against unintended risks.
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Cevap

meticulous (or alternative synonyms such as careful, rigorous, painstaking, thorough, or scrupulous)
The passage argues that because ecological corridors carry both positive benefits and significant risks (such as spreading invasive species), implementing them is a complex strategy. Therefore, the planning involved must be highly detailed and careful. The word 'meticulous' (or synonyms like 'careful' and 'rigorous') precisely conveys this requirement of extreme care and attention to detail.

Adım Adım Çözüm

1
Analyze the context of the sentence containing the blank to determine the relationship between the ideas.
The sentence begins with 'Consequently' and describes the establishment of corridors as a 'complex strategy' that has both 'benefits' and 'unintended risks.'
This establishes that a balanced approach is needed because corridors are not a simple or guaranteed remedy.
2
Identify the type of planning required to achieve this delicate balance between benefits and risks.
To manage complex risks and ensure benefits, the planning must be highly detailed, careful, and precise.
An adjective meaning extremely careful, precise, or thorough is needed to logically complete the description of this planning.

Anahtar Kavram

Words in Context: High-Utility Vocabulary
ÖncekiSayfa 132 / 140Sonraki
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