I have the following problem:
I have the function $f(x,y)=\frac{1}{(2\pi)}(1+x^2+y^2)^{(-3/2)} $.
I have found the quantile function $Q_{T}$ of $T$, where $T=|Y|$, to be: $\tan(\frac{\pi \cdot y}{2})$.
Now I'm asked to caulculate $P(S>s, T>Q_{T}(1-p)$ for $s=4$ and $p=0,25$.
Where $(S,T)=(|X|^{2/5},|Y|)$.
By using the quantile function, and substituting y for p = 0.25 I get $tan(\pi \cdot0.75/2)= 2.4142$
But how do I proceed caulculating $P(S>s, T>Q_{T}(1-p)$?