1. The problem statement, all variables and given/known data http://img710.imageshack.us/img710/4764/doubleintegral.png [Broken] 2. Relevant equations 3. The attempt at a solution Now, my understanding of the region is that x spans from the line x = y to x = 1, and that given that parameter, the applicable y's are 0 to 1. In other words, my region looks like a right triangle with corners at the (0,0), (1,0), (1,1). Since the region ends at the line x = 1 due to the parameters of x, my understanding is that the upper limit on y is effectively 1, and that running it to 3 doesn't do anything. So reversing the order of integration, I get that y will span from 0 to y = x, and x will span from 0 to 1. However, when I click "GO tutorial:" http://img714.imageshack.us/img714/6250/doubleintegral2.png [Broken] And their final answer is .99. This has literally destroyed every ounce of comfort I had with the process. WHY are we running x from 0 to 3 when the order of integration is reversed? That's not in the region!