How to find the probability of X given Y continuous case

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I'm a bit confused about how to calculate conditional distributions. I know that:

$f_{Y|X=x}\left(x,y\right)=\frac{f_{X,Y}\left(x,y\right)}{f_X\left(x\right)}$

Does this mean that for the following joint distribution:

$f(x,y)=\left\{\begin{matrix}\frac{3}{2}&x\in\left(0,1\right)\mathrm{\ and\ } x^2\le y\le1\\0&else\\\end{matrix}\right.$

the calculation to find $f_{Y|X=x}(x,y)$ is:

$f_X\left(x\right)=\int_{\mathbb{R}} f\left(x,y\right)dy=\int_{0}^{1}{\frac{3}{2}dy}=\frac{3}{2}$

combined with:

$f_{Y|X=x}\left(x,y\right)=\frac{f_{X,Y}\left(x,y\right)}{f_X\left(x\right)}$

leading to:

$f_{Y|X=x}\left(x,y\right)=\frac{\frac{3}{2}}{\frac{3}{2}}=1$

If I'm wrong I'd appreciate some help with the general guidelines for finding marginal distributions

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Your calculation of $f_X$ is wrong . $f_X(x)=\int_{x^{2}}^{1} \frac 3 2 \, dx =\frac 3 2 (1-x^{2})$.

When you calculate $f_X(x)$ you fix $x$ and integrate $f_{X,Y}$ w.r.t. $y$. You are integrating $\frac 3 2$ all the way from $0$ to $1$ but remember that when $y <x^{2}$ the function $f_{X,Y}(x,y)$ is given to be $0$. Hence you get integral of $\frac 3 2$ from $x^{2}$ to $1$.