First slide

Trigonometric equations

Question

Sum of the root of the equation $2 \sin^{2} θ + \sin^{2} 2 θ = 2; 0 \leq θ \leq π / 2$ is

Moderate

A

$π / 2$
B

$3 π / 4$
C

$7 π / 2$
D

$5 π / 12$

Solution

$4 \sin^{2} θ \cos^{2} θ = 2 (1 - \sin^{2} θ)$
$\begin{array}{l} \Rightarrow (2 \sin^{2} θ - 1) \cos^{2} θ = 0 \end{array}$
$\begin{array}{l} \Rightarrow \sin^{2} θ = 1 / 2 \end{array}$ or $c {os}^{2} θ = 0$
$\Rightarrow θ = π / 4$ or $θ = π / 2$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App