Find $\frac{d(y^2)}{d(x^2)}$: Understand This Token

[MHD93]

Let y = x^2 + 3x

and the question is Find \frac{dy^2}{dx^2}

then how do I understand this token? is it \frac{d(y^2)}{d(x^2)}
or \frac{(dy)^2}{(dx)^2} = (\frac{dy}{dx})^2
or what ?

BTW: it's not wrong written, namely, not \frac{d^2y}{dx^2}

 

[mathman]

The notation is unusual. I would guess that you let u=x² and v=y², and compute dv/du. Then put x and y back into the result.