[MATH]\frac{d}{dx}(e^{2x} \cdot e^{\sin(4x)})[/MATH]
requires use of the product rule
[MATH]e^{2x} \cdot e^{\sin(4x)} \cdot 4\cos(4x) + e^{\sin(4x)} \cdot 2e^{2x} = 2e^{2x} \cdot e^{\sin(4x)}[2\cos(4x)+1][/MATH]
they are the same expression...
note that [MATH]2e^{2x} \cdot e^{\sin(4x)} = 2e^{2x+\sin(4x)}[/MATH]