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# Joint pdf - find C Watch

1. The joint probability density function is:

The C is a constant.

The ranges are x<1, y<1, x+y>1

They're supposed to be less than or equal to, greater than or equal to.

I am trying to find what the constant C is.

I know the method as I have done similar questions before but this one doesn't seem to be working out for me.

My method: integrate , first with respect to y in between 1-x and 1.

This gives me

I find that odd already with the .

Then integrating again with respect to x between 0 and 1, I get

As the joint pdf equals one, this then gives me

Doesn't look right to me...

Can someone please point out where I went wrong?
2. (Original post by Mathlete29)
...

After integrating wrt y, I get

and then after integrating wrt x, I get

Edit: Both times C, of course.

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