Bro I am getting AC and not BC. The question is simple maybe I am doing a calculation error.
Use the property d2y/dx2=-(dy/dx)^-3 d2x/dy2
Then it will become a simple differential equation.
I got f(x) =|sqrt(4-x^2) | and g(x)=x^2/3
Btw what’s the source of the question?