Respuesta :

Answer: sin (2α) = 2 sin (α) cos (α)

Step-by-step explanation:

We departure from the sin of a sum of angles  

sin ( α + β ) = sinα *cosβ + sinβ *cosα

if α = β   ⇒  sin (α + α ) = sin(α) *cos(α) + sin(α)*cos(α)

sin (2α) = 2 sin (α) cos (α)