1. ## P[x+y<0.4]

My test had a problem that I did not know how to solve.

Let us say we have a joint density function, f(x,y), and it x and y has some region bounded by, etc.

And we want to find p[x+y<0.4] how would we go about solving this?

Thank you,

Sorry if not enough info is given. i just forgot f(x,y) and the region.

2. ## Re: P[x+y<0.4]

Originally Posted by math951
My test had a problem that I did not know how to solve.
Let us say we have a joint density function, f(x,y), and it x and y has some region bounded by, etc.
And we want to find p[x+y<0.4] how would we go about solving this? Sorry if not enough info is given. i just forgot f(x,y) and the region.
Well it is unfortunately the case that your faulty memory makes it almost impossible to help you.
If you recall the question or if you get the test back then repost the question.

3. ## Re: P[x+y<0.4]

Originally Posted by math951
My test had a problem that I did not know how to solve.

Let us say we have a joint density function, f(x,y), and it x and y has some region bounded by, etc.

And we want to find p[x+y<0.4] how would we go about solving this?

Thank you,

Sorry if not enough info is given. i just forgot f(x,y) and the region.
the basic idea is

$P = \displaystyle \int_A f_{X,Y}(x,y)~dx~dy$

where $A$ describes the area over which $x+y < 0.4$ is true