Question

Se x=π/5, o valor de 2.cosπ.sen(π-x).sen(3π/2+x) é igual a:

Answer 1

Boa tarde

Separando as partes, temos:

cos π= -1
sen(π-π/5)= sen(4π/5)= 0,587...
sen(3π/2+π/5)= sen(17π/10)= -0,809...

2(0,587...).(-0,809...)= 0,95105