math: f'(x^x)

Thread Starter

bug13

Joined Feb 13, 2012
2,002
I am stuck with this problem, please explain how to do it, more importantly, why, what concept and what principle is used, thanks

f'(x^x), the answer is: (x^x)*(1+ln(x))
 

steveb

Joined Jul 3, 2008
2,436
I am stuck with this problem, please explain how to do it, more importantly, why, what concept and what principle is used, thanks

f'(x^x), the answer is: (x^x)*(1+ln(x))
Here is a hint. Take any expression. Then take the natural logarithm of it. Then take the exponential of it. That expression is unchanged. In other words take a funtion y(x). The following is true.

y(x)=exp(ln(y))

So, can you find the derivative of exp(ln(x^x))?
 

Thread Starter

bug13

Joined Feb 13, 2012
2,002
your hints is a lot better than WolframAlpha, nice and easy to understand :)

I solved it now, thanks a lot
 
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