Question

The value of $\sin \theta \cos ({90}^0-\theta )+\cos \theta \sin ({90}^0-\theta )$ is:

• A. $1$
• B. $0$
• C. $2$
• D. $-1$

Answer 1

The correct option is A $1$

$\sin \left(\theta \right)\cos (90°-\theta )+\cos \theta \sin (90°-\theta )$

$=\sin \theta .\sin \theta +\cos \theta .\cos \theta$

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

$=1.$

Hence, the answer is $1.$