Simplifying Integration by Parts: Understanding the Solution

Jay9313
Messages
40
Reaction score
0

Homework Statement



∫ln(2x+1) Integrate by parts

Homework Equations



I got xln(2x+1)+\frac{1}2{}ln(2x+1)-x+C

The Attempt at a Solution



The solution is \frac{1}{2}(2x+1)ln(2x+1)-x+C

I know the answers are the same,but it's bugging me that I can't simplify the first answer I got to the second answer. Can someone explain it to me?
 
Physics news on Phys.org
Look at the first two terms of your answer. Is there a common factor there that you can pull out?
 
ln(2x+1) But I don't see how that will help?
 
Oh, you can pull the term out, substitute your x from your u substitution, combine some terms, and you get it! Thanks!
 
Glad I could help :)
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
Back
Top