Question

Calcule o valor de sen y sabendo que cos y = -0,80 e que π/2 < x < π : *

Answer 1

$\large\blue{\boxed{\begin{array}{l}\sf cos\,y=-0,8\implies cos^2\,y=0,64\\\sf sen^2\,y=1-0,64\\\sf sen^2\,y=0,36\\\sf sen\,y=\sqrt{0,36}\\\sf sen\, y=0,6\end{array}}}$