Think, "The derivative of the sine is the cosine. The derivative of e to-the-x is e to-the-x. So the derivative of the product sin(x)e^x may be sung and the parenthises simply filled in.

y = sin(x)e^x

y' = (the derivative of the first) times (the second) + (the derivative of the second) times (the first)

y' = (    )(   ) + (   )(   )

y' = (cos(x))(e^x) + (e^x)(sin(x))

y' = e^x)( cos(x) + sin(x))

                        Stay safe, A²