a=22,5°

sina=sin45°/2=√1-cos45°/2=√1-√2/2/2=√2-√2/2/2=√2-√2/4=√2-√2/2

cosa=cos45°/2=√1+cos45°/2=√1+√2/2/2=√2+√2/2/2=√2+√2/4=√2+√2/2

tga=tg45/2=√1-cos45/1cos45=√1-√2/2/1+√2/2=√2-√2/2+√2/2=√2-√2/2+√2=√(2-√2)²/(2+√2)92-√2)=2-√2/√4-2=(2-√2*√2/√2*√2=2(√2-1)/2=√2-1

a=67.5

sin135/2=√-cos135/2=1-(-√2/2)/2=1√2/2/2=√2+√2/2=√2√/4=√2+2/2

cos135/2=√1+cos135/2=√1(-√2/2)/2=1-√2/2/2=√2-√2/2/2=2-√2/4=2-√2/2