# Partial Fractions

• Nov 24th 2012, 07:52 AM
Nora314
Partial Fractions
Hi everyone! :)

The problem I need help with is:

Preform partial fraction decomposition: x / 4x2 + 4x + 1

In the solution to this exercise the author first factorizes the denominator, which factorizes into (2x + 1)2, but than he writes that

x / (2x + 1)2 = A / (2x + 1) + B / (2x + 1)2, I am unsure why this is the case? I understand that it can't be A / (2x + 1) + B / (2x + 1) either, but the authors approach seems wrong to me (don't worry I know I am wrong, hehe), because (2x + 1)2 is the original factorization of 4x2 + 4x + 1, so adding (2x + 1) to it, would in my eyes give a bigger number than 4x2 + 4x + 1 .

Also, my teacher in Calculus 1 at university said that for the exam it is most important that we learn how to draw graphs and than the rest will come on its own. I assume that was meant as a joke, but he never jokes, so now I am trying to read into his statement to see if there is a underlying hidden message in it.

Thanks to anyone for reading this and helping out :)
• Nov 24th 2012, 08:11 AM
Plato
Re: Partial Fractions
Quote:

Originally Posted by Nora314
Preform partial fraction decomposition: x / 4x2 + 4x + 1

x / (2x + 1)2 = A / (2x + 1) + B / (2x + 1)2, I am unsure why this is the case? I understand that it can't be A / (2x + 1) + B / (2x + 1) either, but the authors approach seems wrong to me (don't worry I know I am wrong, hehe), because (2x + 1)2 is the original factorization of 4x2 + 4x + 1, so adding (2x + 1) to it, would in my eyes give a bigger number than 4x2 + 4x + 1 .

When we add $\displaystyle \frac{x}{(x-2)}+\frac{x+1}{(x-2)^2}$ what is the LCD?

If you see that correctly then you answer your own question.
• Nov 25th 2012, 03:34 AM
Nora314
Re: Partial Fractions
Thank you so much, :D , I understand now!