Input:
`d(f(x)*g(x)*h(x))`
Compute:
$$\frac{d}{dx} f(x)\ g(x)\ h(x)$$
Result:
$$\frac{d}{dx} h(x)\ f(x)\ g(x)+(\frac{d}{dx} g(x)\ f(x)+\frac{d}{dx} f(x)\ g(x))\ h(x)$$
LaTeX:
\frac{d}{dx} h(x)\ f(x)\ g(x)+(\frac{d}{dx} g(x)\ f(x)+\frac{d}{dx} f(x)\ g(x))\ h(x)
$$\frac{d}{dx} f(x)\ g(x)\ h(x) == \frac{d}{dx} h(x)\ f(x)\ g(x)+(\frac{d}{dx} g(x)\ f(x)+\frac{d}{dx} f(x)\ g(x))\ h(x)$$