`cos^2(beta) + cos^2(pi/2 - beta) = 1` Verfiy the identity.

Expert Answers
Borys Shumyatskiy eNotes educator| Certified Educator

`cos(pi/2-b)=sin(b)` for all b.

So the initial identity is equivalent to

`cos^2(b)+sin^2(b)=1,`

which is true.