Given a disc with center at origin and radius one, where
$$f(x,y) = 1/\pi$$
$$\sqrt{x^2+y^2} =1$$
the marginal density function of $X$ is $$2/π * \sqrt{1-x^2}$$
Can the marginal density function of $Y$ be extrapolated without calculation and taken to be the same over $x=1$ and $x=-1$, or is it equal to $2/π$ ?