Question

please answer it's urgent​

Answer 1

Answer:

$= > cos( \frac{\pi}{2} - x)cos( \frac{\pi}{2} - y) - sin( \frac{\pi}{2} - x)sin( \frac{\pi}{2} - y) \\ = > sin \: x \: sin \: y - \: cos \: x \: cos \: y \\ = > - ( cos \: x \: cos \: \: y - \: sin \: x \: sin \: y) \\ = > - cos(x + y)$

Hope you have got it