MHB Finding support for multivariate transformation

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The discussion focuses on the joint transformation of variables (X,Y) into (Z,W) where Z = XY^2 and W = Y, based on the given joint probability density function. The initial support of (X,Y) is rectangular, but the transformation leads to a more complex support for (Z,W). The participants analyze the boundaries of this support, identifying that for the transformed variables, the conditions are 0 < w < 1 and 0 < z < 1, with the additional constraint that √z < w. Ultimately, the support for (Z,W) is described mathematically as 0 < √z < w < 1. This transformation highlights the intricacies of multivariate transformations in probability theory.
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For the given joint pdf of X and Y $$f(x,y) = 12xy(1 - y); 0 < x < 1;
0 < y < 1$$
Let $Z = XY^2$ and $W = Y$ be a joint transformation of (X,Y)

Sketch the graph of the support of $(Z,W)$ and describe it
mathematically.

I'm not very sure how to describe (Z,W).
First, I draw the graph of the support of X and Y, which is a rectangular support.

Now I "map" each interval over to (Z,W).

For $x=0, 0<y<1, z=0, 0<w<1$

For $x=1, 0<y<1, 0<z<w^2, 0<w<1 $

For $y=0, 0<x<1, z=0, w=0$

For $y=1, 0<x<1, 0<z<1, w=1 $

I'm not quite sure how to describe (Z,W), this isn't rectangular neither is it triangular. I have drawn the graph of what I think is the support of (Z,W). How do I describe this quadrant-like support? $0<w<1, 0<z<1, \sqrt{z}<w<1$?
support.jpg
 
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After some figuring out, I determined that the description of the support is all as described in the graph drawn. $0 < \sqrt{z} < w < 1$
 

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