In Leibniz notation, how do you write the second derivative of y with respect to the square of x?

Question

I know how to write in Leibniz notation for more plain-vanilla expressions like the the second derivative of y with respect to x. But I am not sure how to write, in Leibniz notation, the second derivative of y with respect to expressions more complex than a single variable. In, for example, the second derivative of y with respect to the square of x, would I just use parentheses and write $dy^2/d(x^2)^2$?

Answer 1

Indeed, if $z=x^2$ and you need $$ \frac{d^2y}{dz^2} = \frac{d^2 y}{d\left(x^2\right)^2} $$