2 ^2 - 2 ^2 = 1, then = .......^o - Vidyadip

MCQ

$2{\cos ^2}\theta - 2{\sin ^2}\theta = 1$, then $\theta =$ .......$^o$

A
$15$
✓
$30$
C
$45$
D
$60$

✓

Answer

Correct option: B.

$30$

b
(b) $2{\cos ^2}\theta - 2{\sin ^2}\theta = 1$

==> $2\cos 2\theta = 1$

==> $\cos 2\theta = \frac{1}{2} = \cos {60^o}$

==> $2\theta = {60^o}$

$\Rightarrow \theta = {30^o}$.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "MCQ" from 3. trignometrical ratios,functions and identities→3. trignometrical ratios,functions and identities — all question types→MATHS STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

If $\text{i}^2=-1,$ then the sum $\text{i}+\text{i}^2+\text{i}^3+...$ upto 1000 terms is equal to:

If the area of an equilateral triangle inscribed in the circle, $x^2 + y^2 + 10x + 12y + c = 0$ is $27\sqrt 3 \,sq.\,units$ then $c$ is equal to

Suppose that the points $(h, k), (1, 2)$ and $(-3, 4)$ lie on the line $L_1$. If a line $L_2$ passing through the points $(h, k)$ and $(4, 3)$ is perpendicular to $L_1$, then $\frac{k}{h}$ equals

If $\tan \theta = \frac{{\sin \alpha - \cos \alpha }}{{\sin \alpha + \cos \alpha }},$ then $\sin \alpha + \cos \alpha $ and $\sin \alpha - \cos \alpha $ must be equal to

The image of the point $(3,5)$ in the line $x-y+1=0$, lies on

Number of odd numbers of five distinct digits can be formed by the digits $0, 1, 2, 3, 4,$ is:

If $\mathop {\lim }\limits_{x \to \infty } {\left( {1 + \frac{a}{x} - \frac{4}{{{x^2}}}} \right)^{2x}} = {e^3},$ then $'a'$ is equal to

The ${n^{th}}$ term of the following series $(1 \times 3) + (3 \times 5) + (5 \times 7) + (7 \times 9) + .......$ will be

If $a = \cos (2\pi /7) + i\,\sin (2\pi /7),$ then the quadratic equation whose roots are $\alpha = a + {a^2} + {a^4}$ and $\beta = {a^3} + {a^5} + {a^6}$ is

Let $x_n, y_n, z_n, w_n$ denotes $n^{th}$ terms of four different arithmatic progressions with positive terms. If $x_4 + y_4 + z_4 + w_4 = 8$ and $x_{10} + y_{10} + z_{10} + w_{10} = 20,$ then maximum value of $x_{20}.y_{20}.z_{20}.w_{20}$ is-