Question

Как посчитать cos(пи/8)  sin(пи/8) ?

Answer 1

2 * 12 sin π8 * cos π8 = 12 sin π4 = 12 * √22 = √24

Answer 2

сosπ/8=$sqrt{(1+cos pi /4)/2}) = sqrt{(2+ sqrt{2)} } /2$
sinπ/8=$sqrt{(1-cos pi /4)/2}) = sqrt{(2- sqrt{2)} } /2$

Если
cosπ/8*sinπ/8=1/2sinπ/4=1/2*√2/2=√2/4