# Intergrating e

1. Aug 1, 2008

### rugapark

intergrating "e"

I'm doing some intergration q's and I'm stuck on one which involves e

[x^2 e^(x^3) ]dx

I know to integrate you "add one to the power and divide by the new power.. would that make the solution

((x^3)/3) ((e^(x^4))/(x^4)? hope that makes a bit of sense..

2. Aug 1, 2008

### 2slowtogofast

Re: intergrating "e"

try u substition

3. Aug 1, 2008

### nicksauce

Re: intergrating "e"

Nope it doesn't really make sense

First,
$$\int f(x)g(x)dx\neq \int f(x)dx \int g(x)dx$$
Second,
$$\int e^{x^n}dx \neq \frac{e^{x^{n+1}}}{x^{n+1}}$$

That sort of rule only works for the forms x^n and not anything else. The "only" way to integrate an exponential, is to use $$\int e^xdx = e^x$$. In this case, you can't do that directly, but a substituion u = x^3 should do the trick.

Last edited: Aug 1, 2008
4. Aug 1, 2008

### rugapark

Re: intergrating "e"

great - cheers for that i get it now :)