Question

Помогите с домашним заданием!!!

Answer 1

1. sin15° *cos15°=(1/2)*2sin15° *cos15°=(1/2)sin(2*15°)=(1/2)sin30°=(1/2)*(1/2)=1/4

2. tg22°30'/(1-tg²22°30')=tg(2*22°30')=tg45°=1

3. cos²π/8-sin²π/8=cos(2*π/8)=cosπ/4=√2/2