# Partial derivative of a function with exp in it

• May 4th 2010, 11:15 AM
Celicajunkie100
Partial derivative of a function with exp in it
Hi all, I am new here and I hope someone can help with a problem I am having. How can I find the derivative with respect to x of

m(x) = m exp (-x^2/2A^2)

I think what I am looking for is a partial derivative. I have got as far as

dm(x)/dx = (-2x/2A^2) m exp (-x^2/2A^2)

I don't think I need to do anything complex to find the derivative of the (-x^2/2A^2) part of the equation, as it is not in the form f(x)/g(x), rather it is f(x)/"nothing-to-do-with-x"

Is there anything I can do to this formula to make the exp function go away? (I don't want an ln either!)

Many thanks in advance for any help
• May 4th 2010, 12:49 PM
tonio
Quote:

Originally Posted by Celicajunkie100
Hi all, I am new here and I hope someone can help with a problem I am having. How can I find the derivative with respect to x of

m(x) = m exp (-x^2/2A^2)

I think what I am looking for is a partial derivative. I have got as far as

dm(x)/dx = (-2x/2A^2) m exp (-x^2/2A^2)

This is it! Now just simplify and do some order and get $\displaystyle \frac{dm(x)}{dx}=-\frac{mx}{A^2}\,e^{-\frac{x^2}{2A^2}}$

I don't think I need to do anything complex to find the derivative of the (-x^2/2A^2) part of the equation, as it is not in the form f(x)/g(x), rather it is f(x)/"nothing-to-do-with-x"

Is there anything I can do to this formula to make the exp function go away? (I don't want an ln either!)

You can erase it...(Giggle)...but for that nothing: the exp. functions stays in its derivative.

Tonio

Many thanks in advance for any help

.