Найдите -13cos2&,если sin& = -0,1.

Question

Найдите -13cos2&,если sin& = -0,1.

Answer 1

Cos2&=cos^2&-sin^2&
sin^2&=(-0.1)^2=0.01
cos^2&=1-sin^2&=1-0.01=0.99
-13cos2&=-13(0.99-0.01)=-12,74