joint probability density function

[Nickfytas]

Exercise 5.16 . The solution in the back of the book says 55/72 but even though I tried many ways to find the solution it didn’t match , I am probably doing it the wrong way .please help!

 

[tkhunny]

Never trust a distribution that is printed or shared. CHECK IT OUT! What do you get for the TOTAL probability of that thing? If it doesn't sum to UNITY (1), you have bigger problems than simply "doing it wrong". It will help a lot to have the right problem statement.

"600" may be an inadvertent leftover from the previous problem.

 

[Nickfytas]

This exercise is for my calculus 3 assignment and i know only the basis in probability and statistics with one random variable . I calculated the integral in all R2 and in the rectangle that is defined and it doesn’t equal to one in neither cases,
So does that mean that it doesn’t represent a probability destiny function ?
I am convinced that there is something wrong with my approach rather than the exercise having something incorrect.
Thanks for the help

 

[tkhunny]

Find the value of the integral over the entire area. IF you don't get one (1), then something is wrong.

Change 600 to 1650 and see if it works out any better.

 

[Steven G]

You say that you did not get 1 in either case. What cases did you use. Can you please show us your work so we can if you made a mistake or if in fact the result is not one which does mean that it is not a pdf.