If $\cos \theta =\frac{1}{2}(a+\frac{1}{a}),$ then $\cos 2\theta =?$

Important Questions on Trigonometric Functions

MEDIUM

11th CBSE

IMPORTANT

Golden MATHEMATICS CLASS 11>Chapter 3 - Trigonometric Functions>OBJECTIVE TYPE QUESTIONS>Q 13

If $\cos (\alpha +\beta )=m \cos (\alpha -\beta ),$ then $\tan \alpha \tan \beta =$

EASY

11th CBSE

IMPORTANT

Golden MATHEMATICS CLASS 11>Chapter 3 - Trigonometric Functions>OBJECTIVE TYPE QUESTIONS>Q 14

If $\alpha =\frac{\mathrm{\pi }}{20}$ radians, then $\cos \alpha + \cos 2\alpha +...+\cos 20\alpha$ is equal to

MEDIUM

11th CBSE

IMPORTANT

Golden MATHEMATICS CLASS 11>Chapter 3 - Trigonometric Functions>OBJECTIVE TYPE QUESTIONS>Q 15

If $\tan (A+B)· \tan (A-B)=1,$ for all $B\in R, A$ for $n\in 1,$ is

MEDIUM

11th CBSE

IMPORTANT

Golden MATHEMATICS CLASS 11>Chapter 3 - Trigonometric Functions>OBJECTIVE TYPE QUESTIONS>Q 16

The value of $\theta$ satisfying the equation ${\cos }^2\theta +\sin \theta +1=0$ lies in the interval

MEDIUM

11th CBSE

IMPORTANT

Golden MATHEMATICS CLASS 11>Chapter 3 - Trigonometric Functions>OBJECTIVE TYPE QUESTIONS>Q 17

For any angle $x$, the expression $\frac{2\cos 16x+1}{2\cos 2x+1}$ is equal to

HARD

11th CBSE

IMPORTANT

Golden MATHEMATICS CLASS 11>Chapter 3 - Trigonometric Functions>OBJECTIVE TYPE QUESTIONS>Q 18

If $m\tan (\theta +150°)=n\tan (\theta -60°),$ then $\cos 2\theta$ is equal to

EASY

11th CBSE

IMPORTANT

Golden MATHEMATICS CLASS 11>Chapter 3 - Trigonometric Functions>OBJECTIVE TYPE QUESTIONS>Q 19

If $\theta =\frac{\mathrm{\pi }}{8}, \cos \theta + \cos 7\theta =?$

EASY

11th CBSE

IMPORTANT

Golden MATHEMATICS CLASS 11>Chapter 3 - Trigonometric Functions>OBJECTIVE TYPE QUESTIONS>Q 20

If $\sin (\alpha +\beta )=\frac{5}{13}$ and $\cos (\alpha -\beta )=\frac{4}{5}$ and $\alpha , \beta$ lie between $0$ to $\frac{\mathrm{\pi }}{4},$ then $\sin 2\alpha =$