# Math Help - triple integral..

1. ## triple integral..

How to evaluate where is the box determined by
, , and ?

2. Originally Posted by iwonder
How to evaluate where is the box determined by
, , and ?
...It would just be $\int_0^5\int_0^2\int_0^1{ye^{-xy}}dxdydz$

3. After i do the calculations, i still can not find the answer. Can someone help me out? thankyou!

4. Hello,
Originally Posted by iwonder
After i do the calculations, i still can not find the answer. Can someone help me out? thankyou!
The integral can be written this way :

$\left(\int_0^5 dz\right) \left(\int_0^2 \int_0^1 ye^{-xy} ~ dx dy\right)$
because there is no "z" in the integrand.

Now for the second integral, it can be written this way (maybe you'll see more precisely how to proceed) :

$\int_0^2 \left(\int_0^1 ye^{-xy} ~ dx\right) ~ dy$

In order to calculate the integral in the parentheses, if you don't know what to do, make a substitution $t=-xy$

If you still don't get the answer, then it would be nice you show your work