Question

sin10°+2sin5°cos15°+cos50​°

Answer 1

sin10°+2sin5°cos15°+cos50°=sin10°+sin(5°-15°)+sin(5°+15°)+cos50°=sin10°-sin10°+sin20°+cos50°=cos(90°-20°)+cos50°=cos70°+cos50°=2cos(70°+50°):2*cos(70° * 50°):2=2cos60°cos10°=cos10°

Ответ:Cos10°