Calculus

175 soru

Soru 61Soru
Evaluate the trigonometric limit:
limx0cos(3x)cos(x)x2\lim_{x \to 0} \frac{\cos(3x) - \cos(x)}{x^2}
What is the numerical value of this limit?
Cevabı ve açıklamayı göster

Cevap: -4

Cevap

The numerical value of the limit is -4.
Using either the sum-to-product identity cos(3x)cos(x)=2sin(2x)sin(x)\cos(3x) - \cos(x) = -2 \sin(2x) \sin(x) along with standard limits limx0sin(kx)x=k\lim_{x \to 0} \frac{\sin(kx)}{x} = k, or applying L'Hôpital's rule twice on the 00\frac{0}{0} form, yields the exact value 4-4.

Adım Adım Çözüm

1
Check the form of the limit by direct substitution
Substituting x=0x = 0 gives cos(0)cos(0)02=110=00\frac{\cos(0) - \cos(0)}{0^2} = \frac{1 - 1}{0} = \frac{0}{0}, an indeterminate form.
Determines whether algebraic transformation or L'Hôpital's rule is required.
2
Transform the numerator using the sum-to-product formula
\cos(3x) - \cos(x) = -2 \sin\left(\frac{3x+x}{2}\right) \sin\left(\frac{3x-x}{2}\right) = -2 \sin(2x) \sin(x)
Converts difference of cosines into product of sines to utilize standard trigonometric limits.
3
Rewrite the fractional expression and apply limit laws
\lim_{x \to 0} \frac{-2 \sin(2x) \sin(x)}{x^2} = -2 \cdot \left(\lim_{x \to 0} \frac{\sin(2x)}{x}\right) \cdot \left(\lim_{x \to 0} \frac{\sin(x)}{x}\right)
Splits x2x^2 into xxx \cdot x under each sine function.
4
Evaluate the individual standard limits
\lim_{x \to 0} \frac{\sin(2x)}{x} = 2 \quad \text{and} \quad \lim_{x \to 0} \frac{\sin(x)}{x} = 1
Applies the known fundamental trigonometric limit rule limu0sin(au)u=a\lim_{u \to 0} \frac{\sin(au)}{u} = a.
5
Calculate the final product
-2 \times 2 \times 1 = -4
Combines all factors to reach the evaluated value.

Anahtar Kavram

Trigonometric Limits and Indeterminate Forms

Alternatif Yöntem

Alternatively, apply L'Hôpital's rule twice. First derivative of numerator over denominator yields limx03sin(3x)+sin(x)2x\lim_{x \to 0} \frac{-3\sin(3x) + \sin(x)}{2x} (still 00\frac{0}{0}). Differentiating a second time yields limx09cos(3x)+cos(x)2=9(1)+12=82=4\lim_{x \to 0} \frac{-9\cos(3x) + \cos(x)}{2} = \frac{-9(1) + 1}{2} = \frac{-8}{2} = -4.
Tahmini Süre:1m 30s
Soru 62Soru

If y=(2x3)5y = (2x - 3)^5, what is the value of dydx\frac{dy}{dx} at x=2x = 2?

Cevabı ve açıklamayı göster

Cevap: 10

Cevap

10
The derivative of y=(2x3)5y = (2x - 3)^5 with respect to xx requires the chain rule: dydx=5(2x3)4ddx(2x3)=5(2x3)42=10(2x3)4\frac{dy}{dx} = 5(2x - 3)^4 \cdot \frac{d}{dx}(2x - 3) = 5(2x - 3)^4 \cdot 2 = 10(2x - 3)^4. Substituting x=2x = 2 gives 10(2(2)3)4=10(1)4=1010(2(2) - 3)^4 = 10(1)^4 = 10, which makes 1010 the correct value.

Adım Adım Çözüm

1
Identify the inner function u(x)u(x) and outer function f(u)f(u)
Let u=2x3u = 2x - 3, so y=u5y = u^5.
The chain rule states that dydx=dydududx\frac{dy}{dx} = \frac{dy}{du} \cdot \frac{du}{dx}.
2
Differentiate yy with respect to uu and uu with respect to xx
dydu=5u4=5(2x3)4\frac{dy}{du} = 5u^4 = 5(2x - 3)^4 and dudx=2\frac{du}{dx} = 2.
Apply the power rule to both functions.
3
Multiply the derivatives to find dydx\frac{dy}{dx}
dydx=5(2x3)42=10(2x3)4\frac{dy}{dx} = 5(2x - 3)^4 \cdot 2 = 10(2x - 3)^4.
Combine terms using the chain rule formula.
4
Substitute x=2x = 2 into the derivative
dydxx=2=10(2(2)3)4=10(1)4=10\frac{dy}{dx}\Big|_{x=2} = 10(2(2) - 3)^4 = 10(1)^4 = 10.
Evaluate the expression numerically at the target point.

Anahtar Kavram

Chain Rule for Differentiation
Tahmini Süre:45s
Soru 63Soru

Determine the area under the curve y=3x23y = 3x^2 - 3 above the xx-axis between x=1x = 1 and x=3x = 3.

Cevabı ve açıklamayı göster

Cevap: 20

Cevap

The area under the curve between x=1x = 1 and x=3x = 3 is 20 square units.
The area under the curve y=3x23y = 3x^2 - 3 from x=1x = 1 to x=3x = 3 is obtained by calculating the definite integral 13(3x23)dx=[x33x]13=(333(3))(133(1))=18(2)=20\int_{1}^{3} (3x^2 - 3) \, dx = [x^3 - 3x]_{1}^{3} = (3^3 - 3(3)) - (1^3 - 3(1)) = 18 - (-2) = 20.

Adım Adım Çözüm

1
Set up the definite integral representing the area under the curve.
A=13(3x23)dxA = \int_{1}^{3} (3x^2 - 3) \, dx
The area bounded by a non-negative curve y=f(x)y = f(x), the xx-axis, and vertical lines x=ax = a and x=bx = b is given by abf(x)dx\int_{a}^{b} f(x) \, dx.
2
Integrate the polynomial function term by term.
(3x23)dx=x33x+C\int (3x^2 - 3) \, dx = x^3 - 3x + C
Applying the power rule of integration: 3x2dx=x3\int 3x^2 dx = x^3 and 3dx=3x\int 3 dx = 3x.
3
Apply the Fundamental Theorem of Calculus by substituting the limits of integration.
[x33x]13=(333(3))(133(1))=18(2)=20[x^3 - 3x]_{1}^{3} = (3^3 - 3(3)) - (1^3 - 3(1)) = 18 - (-2) = 20
Evaluating F(b)F(a)F(b) - F(a) gives (279)(13)=18(2)=20(27 - 9) - (1 - 3) = 18 - (-2) = 20.

Anahtar Kavram

Definite Integrals and Area Under Curves
Soru 64Soru

A cubic curve defined by y=ax3+bx2+cx+dy = ax^3 + bx^2 + cx + d has a local maximum at (1,10)(-1, 10) and a point of inflexion at (1,2)(1, 2). What is the value of yy at the local minimum of the curve?

Cevabı ve açıklamayı göster

Cevap: -6

Cevap

The local minimum value of yy on the curve is 6-6.
By setting up a system of equations using the conditions for the local maximum at (1,10)(-1, 10) and the point of inflexion at (1,2)(1, 2), the cubic curve is uniquely determined as y=0.5x31.5x24.5x+7.5y = 0.5x^3 - 1.5x^2 - 4.5x + 7.5. Setting the derivative dydx=1.5(x3)(x+1)=0\frac{dy}{dx} = 1.5(x-3)(x+1) = 0 gives x=3x = 3 as the xx-coordinate of the local minimum. Evaluating y(3)y(3) gives 6-6.

Adım Adım Çözüm

1
Differentiate the general cubic equation to obtain expressions for the first and second derivatives.
dydx=3ax2+2bx+c\frac{dy}{dx} = 3ax^2 + 2bx + c and d2ydx2=6ax+2b\frac{d^2y}{dx^2} = 6ax + 2b.
Stationary points require dydx=0\frac{dy}{dx} = 0 and points of inflexion require d2ydx2=0\frac{d^2y}{dx^2} = 0.
2
Apply the point of inflexion conditions at (1,2)(1, 2).
6a(1)+2b=0    b=3a6a(1) + 2b = 0 \implies b = -3a, and a(1)3+b(1)2+c(1)+d=2    2a+c+d=2a(1)^3 + b(1)^2 + c(1) + d = 2 \implies -2a + c + d = 2.
At a point of inflexion, the second derivative is zero, and the point lies on the curve.
3
Apply the stationary point and coordinate conditions at the local maximum (1,10)(-1, 10).
3a(1)2+2b(1)+c=0    9a+c=0    c=9a3a(-1)^2 + 2b(-1) + c = 0 \implies 9a + c = 0 \implies c = -9a, and a+bc+d=10    5a+d=10-a + b - c + d = 10 \implies 5a + d = 10.
At a local maximum, the first derivative is zero, and the point lies on the curve.
4
Solve the system of linear equations for coefficients a,b,c,da, b, c, d.
a=0.5a = 0.5, b=1.5b = -1.5, c=4.5c = -4.5, d=7.5d = 7.5.
Combining 11a+d=2-11a + d = 2 and 5a+d=105a + d = 10 yields 16a=8    a=0.516a = 8 \implies a = 0.5.
5
Find the xx-coordinate of the local minimum by solving dydx=0\frac{dy}{dx} = 0.
1.5x23x4.5=0    1.5(x3)(x+1)=0    x=31.5x^2 - 3x - 4.5 = 0 \implies 1.5(x - 3)(x + 1) = 0 \implies x = 3 (since x=1x = -1 is the local maximum).
Evaluating d2ydx2(3)=6(0.5)(3)+2(1.5)=6>0\frac{d^2y}{dx^2}(3) = 6(0.5)(3) + 2(-1.5) = 6 > 0 confirms a local minimum at x=3x = 3.
6
Calculate the value of yy at x=3x = 3.
y=0.5(3)31.5(3)24.5(3)+7.5=6y = 0.5(3)^3 - 1.5(3)^2 - 4.5(3) + 7.5 = -6.
Substituting x=3x = 3 into the curve equation gives the value of yy at the local minimum.

Anahtar Kavram

Determining polynomial coefficients from stationary and inflexion point conditions to find extreme values.
Soru 65Soru

Using differentiation from first principles, what is the derivative of the function f(x)=3xf(x) = \frac{3}{x} for x0x \neq 0?

Cevabı ve açıklamayı göster

Cevap: 3x2-\frac{3}{x^2}

Cevap

3x2-\frac{3}{x^2}
Using the first principles formula limh0f(x+h)f(x)h\lim_{h \to 0} \frac{f(x+h)-f(x)}{h}, substituting f(x)=3xf(x) = \frac{3}{x} gives limh03x+h3xh=limh03hhx(x+h)=3x2\lim_{h \to 0} \frac{\frac{3}{x+h} - \frac{3}{x}}{h} = \lim_{h \to 0} \frac{-3h}{h x(x+h)} = -\frac{3}{x^2}.

Adım Adım Çözüm

1
Set up the first principles difference quotient
f(x)=limh0f(x+h)f(x)h=limh03x+h3xhf'(x) = \lim_{h \to 0} \frac{f(x+h) - f(x)}{h} = \lim_{h \to 0} \frac{\frac{3}{x+h} - \frac{3}{x}}{h}
Definition of differentiation from first principles.
2
Combine the fractions in the numerator using a common denominator
3x+h3x=3x3(x+h)x(x+h)=3x3x3hx(x+h)=3hx(x+h)\frac{3}{x+h} - \frac{3}{x} = \frac{3x - 3(x+h)}{x(x+h)} = \frac{3x - 3x - 3h}{x(x+h)} = \frac{-3h}{x(x+h)}
Algebraic fraction subtraction.
3
Divide by hh and cancel the common factor
3hx(x+h)h=3x(x+h)\frac{\frac{-3h}{x(x+h)}}{h} = \frac{-3}{x(x+h)}
Simplifying the difference quotient before taking the limit.
4
Evaluate the limit as h0h \to 0
\lim_{h \to 0} \frac{-3}{x(x+h)} = \frac{-3}{x(x+0)} = -\frac{3}{x^2}
Direct substitution of h=0h=0 after canceling hh.

Anahtar Kavram

Differentiation of a reciprocal function using the first principles limit definition.
Soru 66Soru

The line y=5x+cy = 5x + c is tangent to the curve y=x37x+15y = x^3 - 7x + 15 at a point PP located in the first quadrant. What is the equation of the normal line to the curve at point PP?

Cevabı ve açıklamayı göster

Cevap: x+5y47=0x + 5y - 47 = 0

Cevap

The equation of the normal line to the curve at point P is x+5y47=0x + 5y - 47 = 0.
Differentiating the curve yields dydx=3x27\frac{dy}{dx} = 3x^2 - 7. Equating this derivative to the tangent slope of 5 gives x=2x = 2 for the first quadrant. Evaluating the curve equation at x=2x = 2 gives y=9y = 9, locating point P(2,9)P(2, 9). The normal gradient is the negative reciprocal of the tangent slope, giving mn=15m_n = -\frac{1}{5}. Applying the point-slope formula with (2,9)(2, 9) yields y9=15(x2)y - 9 = -\frac{1}{5}(x - 2), which simplifies to x+5y47=0x + 5y - 47 = 0.

Adım Adım Çözüm

1
Find the x-coordinate of the point of tangency P
x=2x = 2
The gradient of the curve dydx=3x27\frac{dy}{dx} = 3x^2 - 7 must equal the gradient of the given line m=5m = 5. Solving 3x27=53x^2 - 7 = 5 gives 3x2=12    x2=4    x=23x^2 = 12 \implies x^2 = 4 \implies x = 2 (since PP is in the first quadrant).
2
Calculate the y-coordinate of point P
y=9y = 9
Substitute x=2x = 2 into the curve equation y=237(2)+15=814+15=9y = 2^3 - 7(2) + 15 = 8 - 14 + 15 = 9. Thus, P=(2,9)P = (2, 9).
3
Determine the gradient of the normal line
mn=15m_n = -\frac{1}{5}
The normal line is perpendicular to the tangent line. Since the tangent gradient mt=5m_t = 5, the normal gradient is mn=1mt=15m_n = -\frac{1}{m_t} = -\frac{1}{5}.
4
Formulate the equation of the normal line
x+5y47=0x + 5y - 47 = 0
Using the point-slope equation yy1=mn(xx1)y - y_1 = m_n(x - x_1) with point (2,9)(2, 9) and gradient 15-\frac{1}{5}: y9=15(x2)    5(y9)=(x2)    5y45=x+2    x+5y47=0y - 9 = -\frac{1}{5}(x - 2) \implies 5(y - 9) = -(x - 2) \implies 5y - 45 = -x + 2 \implies x + 5y - 47 = 0.

Anahtar Kavram

The gradient of the normal to a curve at a given point is the negative reciprocal of the derivative (tangent gradient) at that point: mnormal=1dydxm_{normal} = -\frac{1}{\frac{dy}{dx}}.
Soru 67Soru
A function f(x)f(x) is defined by
f(x)={x2+kx10x2,x27,x=2f(x) = \begin{cases} \frac{x^2 + kx - 10}{x - 2}, & x \neq 2 \\ 7, & x = 2 \end{cases}
If f(x)f(x) is continuous at x=2x = 2, what is the numerical value of the constant kk?
Cevabı ve açıklamayı göster

Cevap: 3

Cevap

The numerical value of the constant kk is 3.
By definition of continuity, f(x)f(x) is continuous at x=2x = 2 if limx2f(x)=f(2)=7\lim_{x \to 2} f(x) = f(2) = 7. As x2x \to 2, the denominator x2x - 2 approaches 00. For the quotient to have a finite limit, the numerator x2+kx10x^2 + kx - 10 must also evaluate to 00 at x=2x = 2, yielding 22+2k10=02^2 + 2k - 10 = 0. Solving this gives 2k=62k = 6, so k=3k = 3. Substituting k=3k = 3 gives limx2(x2)(x+5)x2=7\lim_{x \to 2} \frac{(x-2)(x+5)}{x-2} = 7, confirming that k=3k = 3 is correct.

Adım Adım Çözüm

1
Apply the definition of continuity at x=2x = 2
limx2f(x)=f(2)=7\lim_{x \to 2} f(x) = f(2) = 7
A function f(x)f(x) is continuous at x=ax = a if and only if limxaf(x)=f(a)\lim_{x \to a} f(x) = f(a).
2
Set the numerator to zero at the point of discontinuity x=2x = 2
22+k(2)10=02^2 + k(2) - 10 = 0
Because the denominator (x2)0(x - 2) \to 0 as x2x \to 2, the limit can only exist if the numerator also approaches 00, forming an indeterminate form 00\frac{0}{0} that can be simplified.
3
Solve for the unknown parameter kk
4+2k10=0    2k6=0    k=34 + 2k - 10 = 0 \implies 2k - 6 = 0 \implies k = 3
Linear algebraic equation solving.
4
Verify that the simplified limit equals f(2)f(2)
limx2x2+3x10x2=limx2(x2)(x+5)x2=limx2(x+5)=7\lim_{x \to 2} \frac{x^2 + 3x - 10}{x - 2} = \lim_{x \to 2} \frac{(x - 2)(x + 5)}{x - 2} = \lim_{x \to 2} (x + 5) = 7
Canceling the common factor (x2)(x - 2) yields 77, which matches f(2)=7f(2) = 7.

Anahtar Kavram

Continuity of a Piecewise Function and Limit Existence
Soru 68Soru

What is the indefinite integral (8x3+12cos(4x)5)dx\int (8x^3 + 12\cos(4x) - 5) \, dx?

Cevabı ve açıklamayı göster

Cevap: 2x4+3sin(4x)5x+C2x^4 + 3\sin(4x) - 5x + C

Cevap

2x4+3sin(4x)5x+C2x^4 + 3\sin(4x) - 5x + C
Integrating term by term gives 8x3dx=2x4\int 8x^3 \, dx = 2x^4, 12cos(4x)dx=3sin(4x)\int 12\cos(4x) \, dx = 3\sin(4x), and 5dx=5x\int -5 \, dx = -5x, along with the constant of integration CC, yielding 2x4+3sin(4x)5x+C2x^4 + 3\sin(4x) - 5x + C.

Adım Adım Çözüm

1
Integrate the polynomial term 8x38x^3
8x3+13+1=8x44=2x4\frac{8x^{3+1}}{3+1} = \frac{8x^4}{4} = 2x^4
Apply the power rule for integration: xndx=xn+1n+1\int x^n \, dx = \frac{x^{n+1}}{n+1}.
2
Integrate the trigonometric term 12cos(4x)12\cos(4x)
12sin(4x)4=3sin(4x)12 \cdot \frac{\sin(4x)}{4} = 3\sin(4x)
Apply the standard trigonometric integral rule: cos(kx)dx=1ksin(kx)\int \cos(kx) \, dx = \frac{1}{k}\sin(kx).
3
Integrate the constant term 5-5
5x-5x
The integral of a constant kk with respect to xx is kxkx.
4
Combine all integrated terms and add the arbitrary constant of integration
2x4+3sin(4x)5x+C2x^4 + 3\sin(4x) - 5x + C
An indefinite integral represents a family of functions and requires the addition of +C+ C.

Anahtar Kavram

Indefinite integration of polynomial and trigonometric functions
Tahmini Süre:1m 30s
Soru 69Soru

What is the indefinite integral ((2x3)2+12sin(4x)6cos(3x))dx\int \left( (2x - 3)^2 + 12\sin(4x) - 6\cos(3x) \right) dx?

Cevabı ve açıklamayı göster

Cevap: 43x36x2+9x3cos(4x)2sin(3x)+C\frac{4}{3}x^3 - 6x^2 + 9x - 3\cos(4x) - 2\sin(3x) + C

Cevap

43x36x2+9x3cos(4x)2sin(3x)+C\frac{4}{3}x^3 - 6x^2 + 9x - 3\cos(4x) - 2\sin(3x) + C
Expanding (2x3)2(2x-3)^2 yields 4x212x+94x^2 - 12x + 9. Integrating term by term: 4x2dx=43x3\int 4x^2 dx = \frac{4}{3}x^3, 12xdx=6x2\int -12x dx = -6x^2, 9dx=9x\int 9 dx = 9x, 12sin(4x)dx=3cos(4x)\int 12\sin(4x) dx = -3\cos(4x), and 6cos(3x)dx=2sin(3x)\int -6\cos(3x) dx = -2\sin(3x). Summing these results and adding the constant of integration CC gives 43x36x2+9x3cos(4x)2sin(3x)+C\frac{4}{3}x^3 - 6x^2 + 9x - 3\cos(4x) - 2\sin(3x) + C.

Adım Adım Çözüm

1
Expand the squared binomial inside the integrand.
(2x3)2=4x212x+9(2x - 3)^2 = 4x^2 - 12x + 9
Expanding algebraic terms simplifies the integrand into basic power terms ready for integration.
2
Integrate the polynomial terms using the power rule xndx=xn+1n+1\int x^n dx = \frac{x^{n+1}}{n+1}.
\int (4x^2 - 12x + 9) dx = \frac{4}{3}x^3 - 6x^2 + 9x
Applying the power rule to each term individually gives 4x3312x22+9x\frac{4x^3}{3} - \frac{12x^2}{2} + 9x.
3
Integrate the trigonometric terms using standard integration rules sin(kx)dx=1kcos(kx)\int \sin(kx) dx = -\frac{1}{k}\cos(kx) and cos(kx)dx=1ksin(kx)\int \cos(kx) dx = \frac{1}{k}\sin(kx).
\int 12\sin(4x) dx = -\frac{12}{4}\cos(4x) = -3\cos(4x) and \int -6\cos(3x) dx = -\frac{6}{3}\sin(3x) = -2\sin(3x)
Integrating sine gives negative cosine divided by the inner linear coefficient, and integrating cosine gives sine divided by the inner linear coefficient.
4
Combine all integrated terms and append the constant of integration CC.
\frac{4}{3}x^3 - 6x^2 + 9x - 3\cos(4x) - 2\sin(3x) + C
Indefinite integrals require the addition of an arbitrary constant of integration CC.

Anahtar Kavram

Indefinite Integration of Polynomial and Trigonometric Functions
Soru 70Soru

Given that 0p(6x4)dx=15\int_{0}^{p} (6x - 4) \, dx = 15 and p>0p > 0, what is the value of pp?

Cevabı ve açıklamayı göster

Cevap: 33

Cevap

The value of pp is 33.
Integrating 6x46x - 4 yields 3x24x3x^2 - 4x. Substituting the limits from 00 to pp gives 3p24p3p^2 - 4p. Equating this to 1515 produces the quadratic equation 3p24p15=03p^2 - 4p - 15 = 0, which factors as (3p+5)(p3)=0(3p + 5)(p - 3) = 0. Since p>0p > 0, the only valid solution is 33.

Adım Adım Çözüm

1
Find the indefinite integral of the integrand f(x)=6x4f(x) = 6x - 4.
(6x4)dx=3x24x\int (6x - 4) \, dx = 3x^2 - 4x
Apply the power rule of integration: xndx=xn+1n+1\int x^n \, dx = \frac{x^{n+1}}{n+1}.
2
Evaluate the definite integral from lower limit 00 to upper limit pp.
[3x24x]0p=(3p24p)(0)=3p24p[3x^2 - 4x]_{0}^{p} = (3p^2 - 4p) - (0) = 3p^2 - 4p
Substitute the upper and lower limits into the antiderivative.
3
Set the evaluated definite integral equal to the given value of 1515 and form a quadratic equation.
3p24p15=03p^2 - 4p - 15 = 0
Equate the definite integral value to 15.
4
Factor the quadratic equation to solve for pp.
(3p+5)(p3)=0    p=53(3p + 5)(p - 3) = 0 \implies p = -\frac{5}{3} or p=3p = 3
Find two numbers that multiply to 45-45 and add up to 4-4, which are 9-9 and 55.
5
Select the valid positive value of pp as specified in the question (p>0p > 0).
p=3p = 3
Disregard the negative root since p>0p > 0.

Anahtar Kavram

Determining an unknown boundary limit of a definite integral
Soru 71Soru
A function f(x)f(x) is defined by
f(x)={2x25x3x3,x3k+2,x=3f(x) = \begin{cases} \frac{2x^2 - 5x - 3}{x - 3}, & x \neq 3 \\ k + 2, & x = 3 \end{cases}
If f(x)f(x) is continuous at x=3x = 3, what is the value of the constant kk?
Cevabı ve açıklamayı göster

Cevap: 55

Cevap

The constant value is k=5k = 5.
For the function to be continuous at x=3x = 3, the limit as x3x \to 3 must equal the value of the function at x=3x = 3, which is f(3)=k+2f(3) = k + 2. Factoring the numerator gives 2x25x3=(2x+1)(x3)2x^2 - 5x - 3 = (2x + 1)(x - 3). Canceling the common factor (x3)(x - 3) leaves limx3(2x+1)=7\lim_{x \to 3}(2x + 1) = 7. Setting k+2=7k + 2 = 7 yields k=5k = 5.

Adım Adım Çözüm

1
Evaluate the limit of f(x)f(x) as xx approaches 33
\lim_{x \to 3} \frac{2x^2 - 5x - 3}{x - 3} = \lim_{x \to 3} \frac{(2x + 1)(x - 3)}{x - 3} = \lim_{x \to 3} (2x + 1) = 2(3) + 1 = 7
Direct substitution yields the indeterminate form 00\frac{0}{0}, so the numerator must be factored to cancel the common term (x3)(x - 3).
2
Apply the definition of continuity at x=3x = 3
f(3) = \lim_{x \to 3} f(x) \implies k + 2 = 7
For a function to be continuous at a point x=cx = c, the function value f(c)f(c) must equal the limit of f(x)f(x) as xcx \to c.
3
Solve for the constant kk
k = 7 - 2 = 5
Subtract 22 from both sides of the equation.

Anahtar Kavram

Continuity of a Piecewise Function at a Point
Soru 72Soru

What is the xx-intercept of the normal line to the curve y=x24x+5y = x^2 - 4x + 5 at the point where x=3x = 3?

Cevabı ve açıklamayı göster

Cevap: 7

Cevap

The xx-intercept of the normal line is 7.
Differentiating y=x24x+5y = x^2 - 4x + 5 gives dydx=2x4\frac{dy}{dx} = 2x - 4. Substituting x=3x = 3 yields a tangent gradient of 22, so the normal gradient is 12-\frac{1}{2}. The curve passes through (3,2)(3, 2) at x=3x = 3. The equation of the normal is y2=12(x3)y - 2 = -\frac{1}{2}(x - 3), which simplifies to x+2y7=0x + 2y - 7 = 0. Setting y=0y = 0 gives x=7x = 7.

Adım Adım Çözüm

1
Find the yy-coordinate corresponding to x=3x = 3
y=324(3)+5=912+5=2y = 3^2 - 4(3) + 5 = 9 - 12 + 5 = 2. The point on the curve is (3,2)(3, 2).
The normal line passes through the specific point of tangency on the curve.
2
Calculate the gradient of the tangent and normal lines at x=3x = 3
dydx=2x4\frac{dy}{dx} = 2x - 4. At x=3x = 3, mt=2(3)4=2m_t = 2(3) - 4 = 2. Therefore, mn=1mt=12m_n = -\frac{1}{m_t} = -\frac{1}{2}.
The normal line is perpendicular to the tangent line.
3
Determine the equation of the normal line
y2=12(x3)    2(y2)=(x3)    x+2y7=0y - 2 = -\frac{1}{2}(x - 3) \implies 2(y - 2) = -(x - 3) \implies x + 2y - 7 = 0.
Use the point-slope form yy1=m(xx1)y - y_1 = m(x - x_1) to write the linear equation.
4
Find the xx-intercept of the normal line
Set y=0y = 0: x+2(0)7=0    x=7x + 2(0) - 7 = 0 \implies x = 7.
The xx-intercept occurs where y=0y = 0.

Anahtar Kavram

Tangents and Normals to Curves
Tahmini Süre:1m 30s
Soru 73Soru

What is the result of evaluating the indefinite integral ((2x1)26cos(2x))dx\int \left( (2x - 1)^2 - 6\cos(2x) \right) \, dx?

Cevabı ve açıklamayı göster

Cevap: 43x32x2+x3sin(2x)+C\frac{4}{3}x^3 - 2x^2 + x - 3\sin(2x) + C

Cevap

43x32x2+x3sin(2x)+C\frac{4}{3}x^3 - 2x^2 + x - 3\sin(2x) + C
Expanding the squared term (2x1)2(2x - 1)^2 yields 4x24x+14x^2 - 4x + 1. Integrating term by term using the power rule gives 43x32x2+x\frac{4}{3}x^3 - 2x^2 + x. The integral of 6cos(2x)-6\cos(2x) is 62sin(2x)=3sin(2x)-\frac{6}{2}\sin(2x) = -3\sin(2x). Adding the arbitrary constant CC results in 43x32x2+x3sin(2x)+C\frac{4}{3}x^3 - 2x^2 + x - 3\sin(2x) + C.

Adım Adım Çözüm

1
Expand the squared binomial term inside the integral
(2x1)2=4x24x+1(2x - 1)^2 = 4x^2 - 4x + 1
Expanding the expression allows for term-by-term integration using standard integration rules.
2
Integrate each term of the expanded polynomial
\int (4x^2 - 4x + 1) \, dx = \frac{4}{3}x^3 - 2x^2 + x
Apply the power rule for integration: \int x^n \, dx = \frac{x^{n+1}}{n+1}.
3
Integrate the trigonometric term
\int -6\cos(2x) \, dx = -6 \cdot \frac{1}{2}\sin(2x) = -3\sin(2x)
The standard integral of \cos(kx) is \frac{1}{k}\sin(kx).
4
Combine all integrated terms and append the constant of integration
\frac{4}{3}x^3 - 2x^2 + x - 3\sin(2x) + C
Indefinite integration requires an arbitrary constant of integration C.

Anahtar Kavram

Indefinite Integration of Polynomial and Trigonometric Functions
Soru 74Soru

Using differentiation from first principles, what is the derivative dydx\frac{\mathrm{d}y}{\mathrm{d}x} of the function f(x)=3x22xf(x) = 3x^2 - 2x?

Cevabı ve açıklamayı göster

Cevap: 6x26x - 2

Cevap

The derivative of f(x)=3x22xf(x) = 3x^2 - 2x with respect to xx is 6x26x - 2.
Applying the first principles definition limh0f(x+h)f(x)h\lim_{h \to 0} \frac{f(x+h) - f(x)}{h} to f(x)=3x22xf(x) = 3x^2 - 2x yields 3x2+6xh+3h22x2h(3x22x)h=6xh+3h22hh=6x+3h2\frac{3x^2 + 6xh + 3h^2 - 2x - 2h - (3x^2 - 2x)}{h} = \frac{6xh + 3h^2 - 2h}{h} = 6x + 3h - 2. As h0h \to 0, this simplifies directly to 6x26x - 2.

Adım Adım Çözüm

1
Set up the definition of the derivative from first principles.
dydx=limh0f(x+h)f(x)h\frac{\mathrm{d}y}{\mathrm{d}x} = \lim_{h \to 0} \frac{f(x+h) - f(x)}{h}
The definition of the derivative is the limit of the difference quotient as hh approaches zero.
2
Substitute f(x+h)f(x+h) and f(x)f(x) into the difference quotient.
f(x+h)=3(x+h)22(x+h)=3(x2+2xh+h2)2x2h=3x2+6xh+3h22x2hf(x+h) = 3(x+h)^2 - 2(x+h) = 3(x^2 + 2xh + h^2) - 2x - 2h = 3x^2 + 6xh + 3h^2 - 2x - 2h
Expand (x+h)2(x+h)^2 completely using algebraic identity.
3
Subtract f(x)f(x) from f(x+h)f(x+h) to find the numerator.
f(x+h)f(x)=(3x2+6xh+3h22x2h)(3x22x)=6xh+3h22hf(x+h) - f(x) = (3x^2 + 6xh + 3h^2 - 2x - 2h) - (3x^2 - 2x) = 6xh + 3h^2 - 2h
Cancel out identical terms 3x23x^2 and 2x-2x.
4
Divide by hh and evaluate the limit as h0h \to 0.
\frac{6xh + 3h^2 - 2h}{h} = 6x + 3h - 2; \quad \lim_{h \to 0} (6x + 3h - 2) = 6x - 2
Factor out hh to cancel the denominator, then set h=0h = 0.

Anahtar Kavram

Differentiation from First Principles
Tahmini Süre:1m 30s
Soru 75Soru

Evaluate the definite integral 13(4x36x)dx\int_{1}^{3} (4x^3 - 6x) \, dx.

Cevabı ve açıklamayı göster

Cevap: 56

Cevap

The value of the definite integral is 56.
To evaluate the definite integral 13(4x36x)dx\int_{1}^{3} (4x^3 - 6x) \, dx, integrate the function term-by-term to obtain F(x)=x43x2F(x) = x^4 - 3x^2. Evaluating F(x)F(x) at the upper bound x=3x = 3 yields 5454, and evaluating at the lower bound x=1x = 1 yields 2-2. Subtracting the lower bound value from the upper bound value gives 54(2)=5654 - (-2) = 56.

Adım Adım Çözüm

1
Find the indefinite integral of the function
\int (4x^3 - 6x) \, dx = x^4 - 3x^2
Apply the power rule of integration \int x^n \, dx = \frac{x^{n+1}}{n+1}
2
Substitute the upper limit x = 3 into the antiderivative F(x)
F(3) = 3^4 - 3(3)^2 = 81 - 27 = 54
Evaluate F(b) for b = 3
3
Substitute the lower limit x = 1 into the antiderivative F(x)
F(1) = 1^4 - 3(1)^2 = 1 - 3 = -2
Evaluate F(a) for a = 1
4
Subtract F(a) from F(b)
54 - (-2) = 56
Apply the Fundamental Theorem of Calculus: \int_{a}^{b} f(x) \, dx = F(b) - F(a)

Anahtar Kavram

Definite Integration using the Fundamental Theorem of Calculus
Soru 76Soru

Find the yy-intercept of the tangent line to the curve y=x36x+8y = x^3 - 6x + 8 at the point where x=1x = 1.

Cevabı ve açıklamayı göster

Cevap: 6

Cevap

The yy-intercept of the tangent line is 6.
Differentiating y=x36x+8y = x^3 - 6x + 8 yields dydx=3x26\frac{dy}{dx} = 3x^2 - 6. At x=1x = 1, the point on the curve is (1,3)(1, 3) and the gradient of the tangent is m=3m = -3. Substituting into the point-slope form y3=3(x1)y - 3 = -3(x - 1) gives y=3x+6y = -3x + 6. Setting x=0x = 0 identifies the yy-intercept as 6.

Adım Adım Çözüm

1
Find the point of tangency on the curve
For x=1x = 1, y=(1)36(1)+8=3y = (1)^3 - 6(1) + 8 = 3. The point is (1,3)(1, 3).
The tangent line touches the curve at the point corresponding to x=1x = 1.
2
Find the gradient function of the curve
dydx=3x26\frac{dy}{dx} = 3x^2 - 6
The derivative of the curve equation gives the gradient of the tangent at any point.
3
Calculate the gradient of the tangent line at x=1x = 1
m = 3(1)^2 - 6 = -3
Substitute x=1x = 1 into the derivative.
4
Formulate the equation of the tangent line
y - 3 = -3(x - 1) \implies y = -3x + 6
Apply the point-slope line equation yy1=m(xx1)y - y_1 = m(x - x_1) using (1,3)(1, 3) and m=3m = -3.
5
Determine the yy-intercept
Setting x=0x = 0 yields y=6y = 6.
The yy-intercept is the value of yy when x=0x = 0.

Anahtar Kavram

Tangents to Curves and Axis Intercepts
Soru 77Soru

If y=cos(3x)+exy = \cos(3x) + e^x, what is dydx\frac{dy}{dx}?

Cevabı ve açıklamayı göster

Cevap: 3sin(3x)+ex-3\sin(3x) + e^x

Cevap

3sin(3x)+ex-3\sin(3x) + e^x
Differentiating y=cos(3x)+exy = \cos(3x) + e^x term-by-term yields dydx=3sin(3x)+ex\frac{dy}{dx} = -3\sin(3x) + e^x. By the chain rule, ddxcos(3x)=3sin(3x)\frac{d}{dx}\cos(3x) = -3\sin(3x), while the derivative of exe^x is simply exe^x.

Adım Adım Çözüm

1
Differentiate the trigonometric term cos(3x)\cos(3x) using the chain rule
ddx(cos(3x))=sin(3x)ddx(3x)=3sin(3x)\frac{d}{dx}(\cos(3x)) = -\sin(3x) \cdot \frac{d}{dx}(3x) = -3\sin(3x)
The derivative of cos(u)\cos(u) is sin(u)u-\sin(u) \cdot u'
2
Differentiate the exponential term exe^x
ddx(ex)=ex\frac{d}{dx}(e^x) = e^x
The exponential function exe^x is its own derivative
3
Combine the results using the sum rule
dydx=3sin(3x)+ex\frac{dy}{dx} = -3\sin(3x) + e^x
The derivative of a sum of functions is the sum of their individual derivatives

Anahtar Kavram

Differentiation of trigonometric and exponential functions using the chain rule
Soru 78Soru
A piecewise function f(x)f(x) is defined by
f(x)={2x25x3x3,for x3 a22,for x=3f(x) = \begin{cases} \frac{2x^2 - 5x - 3}{x - 3}, & \text{for } x \neq 3 \ a^2 - 2, & \text{for } x = 3 \end{cases}
If f(x)f(x) is continuous at x=3x = 3 and a>0a > 0, what is the numerical value of aa?
Cevabı ve açıklamayı göster

Cevap: 3

Cevap

The numerical value of a is 3.
For f(x)f(x) to be continuous at x=3x = 3, the defined value f(3)=a22f(3) = a^2 - 2 must equal limx3f(x)\lim_{x \to 3} f(x). Factoring the numerator gives (2x+1)(x3)x3=2x+1\frac{(2x + 1)(x - 3)}{x - 3} = 2x + 1 for x3x \neq 3. Taking the limit as x3x \to 3 yields 2(3)+1=72(3) + 1 = 7. Setting a22=7a^2 - 2 = 7 leads to a2=9a^2 = 9, which gives a=3a = 3 under the constraint a>0a > 0.

Adım Adım Çözüm

1
Evaluate the limit of f(x)f(x) as x3x \to 3
Factor the numerator 2x25x3=(2x+1)(x3)2x^2 - 5x - 3 = (2x + 1)(x - 3). For x3x \neq 3, f(x)=2x+1f(x) = 2x + 1. Thus, limx3f(x)=2(3)+1=7\lim_{x \to 3} f(x) = 2(3) + 1 = 7.
Direct substitution gives an indeterminate form 00\frac{0}{0}, so canceling the common factor (x3)(x - 3) allows direct evaluation of the limit.
2
Apply the definition of continuity at x=3x = 3
f(3)=a22=7f(3) = a^2 - 2 = 7.
For a function to be continuous at a point cc, the function value f(c)f(c) must equal the limit limxcf(x)\lim_{x \to c} f(x).
3
Solve for the parameter aa
a2=9    a=3a^2 = 9 \implies a = 3 (since a>0a > 0).
Solving a2=9a^2 = 9 gives solutions 33 and 3-3. The condition a>0a > 0 specifies the positive root.

Anahtar Kavram

Continuity of a Piecewise Function at a Point
Soru 79Soru

If y=x3(2x1)4y = x^3(2x - 1)^4, find the value of dydx\frac{dy}{dx} at x=1x = 1.

Cevabı ve açıklamayı göster

Cevap: 11

Cevap

The numerical value of dydx\frac{dy}{dx} at x=1x = 1 is 1111.
Applying the product rule dydx=udvdx+vdudx\frac{dy}{dx} = u\frac{dv}{dx} + v\frac{du}{dx} along with the chain rule for the expression (2x1)4(2x - 1)^4 gives dydx=8x3(2x1)3+3x2(2x1)4\frac{dy}{dx} = 8x^3(2x - 1)^3 + 3x^2(2x - 1)^4. Evaluating this at x=1x = 1 gives 8(1)3(1)3+3(1)2(1)4=8+3=118(1)^3(1)^3 + 3(1)^2(1)^4 = 8 + 3 = 11.

Adım Adım Çözüm

1
Set up the product rule for y=uvy = u \cdot v, where u=x3u = x^3 and v=(2x1)4v = (2x - 1)^4.
u=x3u = x^3 and v=(2x1)4v = (2x - 1)^4
The function is expressed as the product of two algebraic terms.
2
Find the derivative of each function component.
dudx=3x2\frac{du}{dx} = 3x^2 and dvdx=8(2x1)3\frac{dv}{dx} = 8(2x - 1)^3
The power rule gives dudx=3x2\frac{du}{dx} = 3x^2, and applying the chain rule to (2x1)4(2x - 1)^4 yields 4(2x1)32=8(2x1)34(2x - 1)^3 \cdot 2 = 8(2x - 1)^3.
3
Substitute components into the product rule formula dydx=udvdx+vdudx\frac{dy}{dx} = u\frac{dv}{dx} + v\frac{du}{dx}.
dydx=8x3(2x1)3+3x2(2x1)4\frac{dy}{dx} = 8x^3(2x - 1)^3 + 3x^2(2x - 1)^4
Combining udvdxu\frac{dv}{dx} and vdudxv\frac{du}{dx} provides the full expression for the derivative.
4
Evaluate the derivative at x=1x = 1.
dydxx=1=8(1)3(2(1)1)3+3(1)2(2(1)1)4=8+3=11\frac{dy}{dx}\Big|_{x=1} = 8(1)^3(2(1) - 1)^3 + 3(1)^2(2(1) - 1)^4 = 8 + 3 = 11
Substituting x=1x = 1 simplifies the terms to 8(1)+3(1)=118(1) + 3(1) = 11.

Anahtar Kavram

Rules of Differentiation (Product and Chain Rules)
Soru 80Soru

If y=ln(sec3x+tan3x)y = \ln(\sec 3x + \tan 3x), what is dydx\frac{dy}{dx}?

Cevabı ve açıklamayı göster

Cevap: 3sec3x3\sec 3x

Cevap

3sec3x3\sec 3x
Using the chain rule for y=lnuy = \ln u where u=sec3x+tan3xu = \sec 3x + \tan 3x, we find u=3sec3xtan3x+3sec23x=3sec3x(tan3x+sec3x)u' = 3\sec 3x\tan 3x + 3\sec^2 3x = 3\sec 3x(\tan 3x + \sec 3x). Dividing uu' by uu cancels out (sec3x+tan3x)(\sec 3x + \tan 3x), leaving 3sec3x3\sec 3x.

Adım Adım Çözüm

1
Apply the chain rule for logarithmic functions ddx[ln(u)]=1ududx\frac{d}{dx}[\ln(u)] = \frac{1}{u}\frac{du}{dx}.
Set u=sec3x+tan3xu = \sec 3x + \tan 3x, so dydx=1sec3x+tan3xddx(sec3x+tan3x)\frac{dy}{dx} = \frac{1}{\sec 3x + \tan 3x} \cdot \frac{d}{dx}(\sec 3x + \tan 3x).
The function is a composite function of the form y=ln(u(x))y = \ln(u(x)).
2
Differentiate the inner function u=sec3x+tan3xu = \sec 3x + \tan 3x using the chain rule.
\frac{du}{dx} = 3\sec 3x \tan 3x + 3\sec^2 3x.
The derivative of sec(ax)\sec(ax) is asec(ax)tan(ax)a\sec(ax)\tan(ax) and the derivative of tan(ax)\tan(ax) is asec2(ax)a\sec^2(ax).
3
Factor out common terms in the numerator and simplify the expression.
\frac{dy}{dx} = \frac{3\sec 3x(\tan 3x + \sec 3x)}{\sec 3x + \tan 3x} = 3\sec 3x.
The term (tan3x+sec3x)(\tan 3x + \sec 3x) in the numerator cancels with the denominator (sec3x+tan3x)(\sec 3x + \tan 3x).

Anahtar Kavram

Differentiation of Logarithmic and Trigonometric Functions via the Chain Rule
Tahmini Süre:1m 30s
ÖncekiSayfa 4 / 9Sonraki
Calculus Alıştırma Soruları — JAMB UTME — Sayfa 4 | Examkin