Question

Difficulty: MediumBasic Trigonometric Ratios, Special Angles, and Identities

Simplify the trigonometric expression tan60+sin45cos45\frac{\tan 60^\circ + \sin 45^\circ}{\cos 45^\circ} to its exact surd form.

  1. 6+1\sqrt{6} + 1Answer
  2. B
    102\frac{\sqrt{10}}{2}
  3. C
    3+63\frac{3 + \sqrt{6}}{3}
  4. D
    3+1\sqrt{3} + 1

Answer

6+1\sqrt{6} + 1
Substituting the exact values gives tan60=3\tan 60^\circ = \sqrt{3}, sin45=12\sin 45^\circ = \frac{1}{\sqrt{2}}, and cos45=12\cos 45^\circ = \frac{1}{\sqrt{2}}. Simplifying 3+1/21/2\frac{\sqrt{3} + 1/\sqrt{2}}{1/\sqrt{2}} gives 32+1=6+1\sqrt{3} \cdot \sqrt{2} + 1 = \sqrt{6} + 1.

Step-by-Step Solution

1
Substitute the exact trigonometric values for the special angles
tan60=3\tan 60^\circ = \sqrt{3}, sin45=12\sin 45^\circ = \frac{1}{\sqrt{2}}, and cos45=12\cos 45^\circ = \frac{1}{\sqrt{2}}
Special angle values must be expressed in exact surd form.
2
Set up the fractional expression
3+1212\frac{\sqrt{3} + \frac{1}{\sqrt{2}}}{\frac{1}{\sqrt{2}}}
Replace each ratio with its exact surd equivalent.
3
Divide numerator terms by the denominator
312+1212=32+1=6+1\frac{\sqrt{3}}{\frac{1}{\sqrt{2}}} + \frac{\frac{1}{\sqrt{2}}}{\frac{1}{\sqrt{2}}} = \sqrt{3} \cdot \sqrt{2} + 1 = \sqrt{6} + 1
Dividing by a fraction is equivalent to multiplying by its reciprocal.

Key Concept

Evaluation of Special Angle Trigonometric Ratios and Simplification of Surds
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