Question

encontre o valor de:

sen 120° x cos 120°

Sen 315° x cos 315°

Answer 1

$\mathsf{sen(120^{\circ})\times\,cos(120^{\circ})=\dfrac{\sqrt{3}}{2}\times(-\dfrac{1}{2})}\\=\large\boxed{\boxed{\boxed{\boxed{\mathsf{-\dfrac{\sqrt{3}}{4}}}}}}$

$\mathsf{sen(315^{\circ})\times\,cos(315^{\circ})=\dfrac{-\sqrt{2}}{2}\times(\dfrac{\sqrt{2}}{2})}\\=\large\boxed{\boxed{\boxed{\boxed{\mathsf{-\dfrac{1}{2}}}}}}$