Question

A expressão sen(X+Y)+sen(X+Y) é:

a)-2senx.cosy

b)2senx.cosy

c)2senx.cosy+2seny.cosy

d)2seny.cosx+2senx.cosy

e)2senx.cosy-2seny.cosx

Answer 1

$sen(x+y)+sen(x+y)=2sen(x+y)=\\ \\ 2[sen(x).cos(y)+sen(y)cos(x)]\\ \\ =\boxed{2sen(x)cos(y)+2sen(y)cos(x)}$