Question

Verify the identity

cos(x + pi/2) = -sin x

Answer 1

Using our Angle Addition Formula for Cosine:\[\Large\rm \cos\left(x+\frac{\pi}{2}\right)=\cos x \cos \frac{\pi}{2}-\sin x \sin \frac{\pi}{2}\]Understand how to simplify it from there?

Answer 2

would it be cos x(0) -sin x(1) ?

Answer 3

Mmm yes very good!

Answer 4

yayy thank you so much!