Which way is correct to represent this differentiation? $$3x^2+x^3$$
Option 1
$$\frac{d}{dx}(3x^2+x^3)=6x+3x^2$$
Option 2
$$\frac{d(3x^2+x^3)}{dx}=6x+3x^2$$
My student wrote the Option 2 style, not sure whether I can consider is ok or not.

Both of the given representations are equivalent.
For:
$$y(x)=3x^2+x^3$$
$$\frac{dy}{dx} \equiv \frac{d(3x^2+x^3)}{dx} \equiv \frac{d}{dx}(3x^2+x^3) \equiv  \frac{d(3x^2)}{dx}+\frac{d(x^3)}{dx} \equiv \frac{d}{dx}(3x^2)+\frac{d}{dx}(x^3) 
=6x+3x^2$$
