Using Euler's equation {e^i(x+y) = e^(ix) * e^(iy) prove (1)

Last updated: 7/31/2022

Using Euler's equation {e^i(x+y) = e^(ix) * e^(iy) prove (1) sin x + sin y = 2sin{(x + y)/2} * cos{(x - y)/2} (2) sin x cos y = {sin(x + y) + sin( x - y)} / 2 (3) cos x cos y = {cos(x + y) - cos(x - y)} / 2