those bounds are correct, they are two triangles
it's good to see that you drew the region
otherwise it's nearly impossible to figure out the bounds
May I obtain critiques/hints/tips on my approach?
Q1) I evaluated the double integral and it was equal to 1. I also substituted x=10, 20 into the function and confirmed it is >0
Q2) I drew the graph for limits of integration
For the marginal density of x I have:
For the marginal density of y I have:
May I ask if my bounds correct in calculating this?
Q3) I had:
Q4) I feel it is related to Q3, and wanted to see if I have Q3 correct first