View Full Version : help with derivatives of natural logs
musiciskey
Oct15-09, 05:33 PM
1. The problem statement, all variables and given/known data
(ln(1+e^x))^6
2. Relevant equations
3. The attempt at a solution
Honestly I haven't done this in 3 years and a friend asked me to help them with it. I'm at a bit of loss.
I'll help you with one of the steps.
d/dx[ (ln(1+ex))6] = 6(ln(1 + ex)5* d/dx(ln(1 + ex))
Is that enough of a start?
musiciskey
Oct15-09, 08:05 PM
I'll pass it on to her and find out. Thanks.
There's a difference between (ln(1+ex))6 and ln(1+ex)6 = ln[(1+ex)6]
The ln has the exponent, not the argument of the ln, so you can't pull the exponent out in front.
There's a difference between (ln(1+ex))6 and ln(1+ex)6 = ln[(1+ex)6]
The ln has the exponent, not the argument of the ln, so you can't pull the exponent out in front.
I understand that there is a difference.
The problem as posted is
(ln(1+e^x))^6
As you can see, it was NOT ln(1 + ex)6, as you seem to think.
Because the log expression is raised to the 6th power, the derivative is 6( ln(1 + ex))5 * d/dx(ln(1 + ex)).
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