Question:
Differentiate w.r.t $x: e^{2 x} \sin 3 x$
Solution:
Let $y=e^{2 x} \sin 3 x, z=e^{2 x}$ and $w=\sin 3 x$
Formula :
$\frac{d\left(e^{x}\right)}{d x}=e^{x}$ and $\frac{d(\sin x)}{d x}=\cos x$
According to product rule of differentiation
$\mathrm{dy} / \mathrm{dx}=\mathrm{w} \times \frac{\mathrm{dz}}{\mathrm{dx}}+\mathrm{z} \times \frac{\mathrm{dw}}{\mathrm{dx}}$
$=\left[\sin 3 x \times\left(2 \times e^{2 x}\right)\right]+\left[e^{2 x} \times 3 \cos 3 x\right]$
$=e^{2 x} \times[2 \sin 3 x+3 \cos 3 x]$