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malteseboy

Member

Registered: 2009-11-18

Posts: 1

Partial Fractions

Express in partial fractions:

a) (3x + 1) / (x + 1)^2

b) (x^2 + 7x + 2) / (1 + x^2)(2 - x)

Show me the working pls.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Partial Fractions

Hi malteseboy;

First, go here for all the traditional ways of doing these.

http://en.wikipedia.org/wiki/Partial_fraction

Now let's look at my way for a.

For multiplicities in the denominator: the partial fraction will take the form:

With A and B to be determined. If you evaluate (3x+1) / (x+1)^2 for x = 0 you get 1. Also if you evaluate (3x+1) / (x+1)^2 for x = 1 you get 1.

Using both those values of 1 and 1 we can now form a simultaneous set of equations for A and B.

Solve this set for A and B and you are done. Try the next one and post if you get stuck.

Last edited by bobbym (2009-11-18 07:15:43)

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