(850, #39) Evaluate the integral by reversing the order of integration for

.

Solution: In the integral y is held fixed and x ranges from 3y to 3:

When the order is reversed x is held fixed on the interval [0,3] and y ranges from 0 to x/3.

Evaluating the reversed integral:

Maple Check:

int( int( exp(x^2), y = 0..x/3), x = 0..3);

1/6 exp(9) - 1/6

by: gm