Question

Calcular sen2x, sabendo que o senx = 2/3.

Answer 1

Explicação passo-a-passo:

sen²x+cos²x=1

(2/3)²+cos²x=1

4/9+cos²x=1

cos²x=1-4/9

cos²x=5/9

cosx=r5/3

sen (a+b)=sena.cosb+senb.cosa

sen(x+x)=senx.cosx+senx.cosx

sen(2x)=2senxcosx

sen(2x)=2.2/3.r5/3

sen(2x)=4.r5/9