Cos45-sin^2 150+cos120=

Question

Cos45-sin^2 150+cos120=

Answer 1

Cos45=корень(2) /2
sin150=1/2
cos120=-1/2

значит cos45-sin^2 150+cos120=корень(2)/2-1/4-1/2=(2*корень(2)-3)/4