`y=sin(e^(3x))`

Let `y=sin\ u`, where `u=e^(3x)`

`(dy)/(dx)=(dy)/(du)(du)/(dx)`

`=[cos\ u](d(e^(3x)))/(dx)`

`=[cos\ e^(3x)](3e^(3x))`

`=3e^(3x)\ cos\ e^(3x)`