С. 1. cos135-sin150= 2, sin120°*cos150°*tg135°*sin2 - вопрос №330714511351502120150135245 от Umarinavitalevna 03.03.2020 21:09

Question

Геометрия: С. 1. cos135-sin150= 2, sin120°*cos150°*tg135°*sin2 45°

Umarinavitalevna · Answer

Сos135 - sin150=cos(180-45) - sin(180-30)= - cos45 - sin30=
= - √2/2 - 1/2= - (√2+1)/2
sin120·cos150·tg135·sin²45=sin(180 - 60)·cos(180 - 30)·tg(180 - 45)·(√2/2)²=sin60·( - cos30)·( - tg45)·1/2=√3/2·√3/2·1·1/2=3/8