Cosx-sinx=0.5 cosx+sinx=0.7cos2x-?

Question

Cosx-sinx=0.5
cosx+sinx=0.7
cos2x-?

Answer 1

Cos2x=cos^2x-sin^2x=(cosx-sinx)(cosx+sinx)=0,5*0,7= 0,35 Ответ:0,35