Example 1.21
Convert the following multiple integral to a single integral:
x x1 u(x )dx dx. (1.131)
2 1
0 0
Using the formula (1.129) we obtain
x x1 u(x )dx dx = x (x − t)u(t)dt. (1.132)
2 1
0 0 0
Example 1.22
Convert the following multiple integral to a single integral:
x x1 x2 u(x )dx dx dx. (1.133)
3 2 1
0 0 0
Using the formula (1.129) we obtain
x x1 x2 1 x 2
u(x )dx dx dx = (x − t) u(t)dt. (1.134)
3 2 1
0 0 0 2! 0