Uniform distribution on the disc

[mathmathmad]

Homework Statement

consider a disc of radius 1 in the plane D in R^2
D = {(x,y) in R^2 | x^2 + y^2 <=1 }
what is the marginal pdf of x and y

Homework Equations

The Attempt at a Solution

so the joint distribution of xy is 1/Pi for x^2 + y^2 <=1 right?
but how exactly? "density" = "probability" / "area"
area = Pi since Pi*(1)^2 what about the probability? why is it 1?

what is the marginal pdf of x and y?
is it integral of 1/Pi from -infinity to +infinity wrt to y for marginal pdf of x?

 

[statdad]

why did you post this in two locations? look at your other post.

 

[mathmathmad]

yikes I'm sorry! didn't notice I double posted
I was curious when I couldn't find my topic and thought that I haven't posted it...
https://www.physicsforums.com/showthread.php?p=2955953#post2955953