Evaluating an indefinite integral

Wm_Davies
Messages
51
Reaction score
0

Homework Statement


Evaluate the indefinite integral.

\int \left({\sqrt[5]{x^5}}-\frac{6}{5 x}+\frac{1}{4 x^{7}} \right) dx


The Attempt at a Solution



O.k. the only anti-derivative I am having trouble getting is the first one {\sqrt[5]{x^5}}.

I am not sure what formula I would use or how to do it. I looked through the book, but I didn't see anything addressing this. Any help would be appreciated.

I imagine that it would be easier to write it as (x^{5})^{\frac{1}{5}}

Working through it I get (\frac{x^{6}}{6})^{\frac{1}{5}}

then I am stuck...
 
Physics news on Phys.org
Remember that when you raise a power to a power, that by the Law of Exponents the powers multiply. :wink:
 
Simplify first!
\sqrt[5]{x^5}~=~x
 
Mark44 said:
Simplify first!
\sqrt[5]{x^5}~=~x

Yeah, I can't believe I missed that. So then the anti-derivative should be \frac{x^{2}}{2} + a constant?
 
Yes, but you won't need a constant for each term in the integrand - just one for all three.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top