Question

 sa se calculeze : sin la puterea 2 de 50 de grade + sin la puterea 2 de 40 de grade. Multumesc

Answer 1

Salut,

sin(90° -- x) = cosx

sin²50° + sin²40° = sin²(90° -- 40°) + sin²50° = cos²50° + sin²50° = 1.

Green eyes.

Answer 2

$\it sin40^o =cos(90^o-40^o) =cos50^o \Rightarrow sin^240^o=cos^250^o$

Expresia din enunț devine:

$\it sin^2 50^o+cos^2 50^o = 1$

Am folosit formula fundamentală a trigonometriei :

$\it sin^2x+cos^2x=1$