Question

sin 3 pi/4*cos pi/4+cos 3 pi/4*sin pi/4

Answer 1

$frac{ sqrt{2} }{2} * frac{ sqrt{2} }{2} + frac{ sqrt{2} }{2} * frac{ sqrt{2} }{2} = frac{1}{2} +frac{1}{2} =1$