Question

How do you prove `sin(pi/4 + x) = cos (pi/4 - x)`?

Answer 1

Expand the terms and use the identity `sin^2(x) + cos^2(x) = 1`

sin(π/4) + sin x = cos(π/4) − cos x)

sin x = 1 − cos x
sin(x) + cos(x) = 1

`sin^2(x) + cos^2(x) = 1`