Question

$\theta$ satisfying , $sin2\theta$ + $cos2\theta$ = 1 are ${90}^{\circ }$ and ${45}^{\circ }$

• A. True
• B. False

Answer 1

The correct option is A

True

sin 2$\theta$ + cos 2$\theta$ = 1

2 sin$\theta$ cos$\theta$ + ${cos}^2\theta$ – ${sin}^2\theta$ = 1

2 cos$\theta$ [ sin$\theta$ – cos$\theta$] = 0

cos$\theta$ = 0, sin$\theta$ = cos $\theta$

θ = ${90}^{\circ }$ , θ = ${45}^{\circ }$