please help

[kim270]

i need help with finding the intergal of

f(x)= xe^-x^2
e^-x^2= natural logarithm to the power of -x squared

i have no idea how to do this

 

[stapel]

Do you mean that you are trying to find the indefinite integral of ex - x²? (Your formatting is ambiguous, which is why I'm asking.)

The rule for integrating polynomial terms, which appears to be what you're doing, is:

. . . . .\(\displaystyle \large{\int{ax^n}\mbox{ }dx \mbox{ }= \mbox{ } \frac{a}{n}\mbox{ }x^{n+1}}\)

Apply this to your exercise (or else reply with corrections and/or clarifications).

Thank you.

Eliz.

 

[kim270]

i tried to clarify my question as best as i could

hope that can help

 

[stapel]

So, by "natural logarithm", you mean "natural exponential", and your subtraction was actually an exponent. The integral is:

. . . . .\(\displaystyle \large{\int{xe^{-x^2}}\mbox{ }dx}\)

In that case, have you considered u-substitution, with u = -x²? The integration should go very smoothly.

Eliz.

 

[kim270]

thanks that helps