Решите!!! соs(10) sin (80) + sin^2 (280) соs^2 (100) + sin^2 (170) sin^2 (350) =

Решите задачу:

$cos10\cdot sin80+sin^2280\cdot cos^2100+sin^2170\cdot sin^2350=\\\\=cos10\cdot sin(90-10)+sin^2(270+10)\cdot cos^2(90-10)+\\\\+sin^2(180-10)\cdot sin^2(360-10)=\\\\=cos10\cdot cos10+cos^210\cdot sin^210+sin^210\cdot sin^210=\\\\=cos^210+sin^210(cos^210+sin^210)=\\\\=cos^210+sin^210\cdot 1=cos^210+sin^210=1$