Drexel dragonThe Math ForumDonate to the Math Forum

Ask Dr. Math - Questions and Answers from our Archives
_____________________________________________
Associated Topics || Dr. Math Home || Search Dr. Math
_____________________________________________

Simplifying and Solving a Natural Log Problem


Date: 11/15/95 at 12:40:58
From: Anonymous
Subject: integration of ln(r/a)dr

Integrate ln(r/a)dr -- the limits are a to b.  Is this possible, or is there
some table for this??  Thanx.


Date: 12/14/95 at 22:10:23
From: Doctor Ken
Subject: Re: integration of ln(r/a)dr

Hello!

The first thing I think I'd do is to simplify the problem a little bit.
You can actually make the "a" not matter so much in this problem by 
noticing that ln(r/a) = ln(r) - ln(a), and ln(a) is just a constant.  
Then you can apply the antiderivative of Natural Log: it's r*ln(r) - r.

Good luck!

-Doctor Ken,  The Geometry Forum

    
Associated Topics:
High School Calculus

Search the Dr. Math Library:


Find items containing (put spaces between keywords):
 
Click only once for faster results:

[ Choose "whole words" when searching for a word like age.]

all keywords, in any order at least one, that exact phrase
parts of words whole words

Submit your own question to Dr. Math

[Privacy Policy] [Terms of Use]

_____________________________________
Math Forum Home || Math Library || Quick Reference || Math Forum Search
_____________________________________

Ask Dr. MathTM
© 1994-2013 The Math Forum
http://mathforum.org/dr.math/