Integral of inverse trig or inverse hyperbolic

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Homework Statement



∫5/(4x√(9-16x2)dx

Homework Equations



I am pretty sure this is in the form of ∫du/(u√(a2-u2)

The Attempt at a Solution



setting u=4x a=3 and du=4dx so 1/4du=dx I get:

-5/12 sech-1(4x/3) + C

Is this right or am I using the wrong definition? Just trying to check my answers

Thanks for any help
 
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Yes, that is correct.
 
Thanks, I really appreciate it!

One quick follow-up question to anyone who can help:

Some of the integral definitions involving hyperbolic inverse functions call for if a>u or u>a. I know that dealing with a definite integral we just use the limits of integration to figure that out, but what if we are dealing with an indefinite integral? How do you know then?
 
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...

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