How do you simplify sin(90 + x)?

## sin (90 + x) = cos x ##
## sin (90 + x) = cos x ##
Method 1: Using plots of ##sin x## and ##cos x##. A shift of -90 degrees of ##sin x## gives you ##cos x##
Method 2: ##sin (A +- B) = sin A cos B +- cos A sin B ##