Question

sin theta sin 90 - theta minus cos theta cos 90 - theta is equal to zero prove this

Answer 1

$\textbf{Given:}$

$sin\theta\;sin(90-\theta)-cos\theta\;cos(90-\theta)$

$\text{Using,}$

$\boxed{\bf\,sin(90-\theta)=cos\theta}$

$\boxed{\bf\,cos(90-\theta)=sin\theta}$

$=sin\theta\;cos\theta-cos\theta\;sin\theta$

$=sin\theta\;cos\theta-sin\theta\;cos\theta$

$=0$

$\implies\,\boxed{\mathsf{sin\theta\;sin(90-\theta)-cos\theta\;cos(90-\theta)=0}}$

Find more:

Solve without using trigonometric tables

(tan 20 / cot 70)+(cot 50 / tan 40 ) +((sin2 20 + sin2 70 )/ sin theta cos (90 - theta ) +cos theta sin (90 - theta)

https://brainly.in/question/8196799#