# Homework Help: Partial fraction help

1. May 17, 2010

### kokkie_d

1. The problem statement, all variables and given/known data

Hi,

I have the following problem. These two equations are the same but I can not find the right route from one to the other. Is there someone who can help me?
In other words, I start with the equation on the left and want to end with the equation on the right.

2. Relevant equations

1/(s(1+RCs)) = 1/s - 1/(s + 1/RC)

3. The attempt at a solution
1/(s(1+RCs)) multiply top and bottom by 1-RCs
= (1-RCs) / (s * (1+RCs) * (1-RCs))
= (1-RCs) / (s - (RCs^2) * s)
= (1 / s) - 1 / (RCs*s)

Cheers

2. May 17, 2010

### Staff: Mentor

Start from the right side. Multiply the first fraction by (s + 1/RC) over itself. Multiply the second fraction by s over itself.

3. May 17, 2010

### MisterMan

Alternatively to the way Mark44 did it, you could also split the fraction you have on the left up into two fractions. Then multiply the separate fractions by the opposing denominator, that's a starting point. See if you can work it out from there.

Last edited: May 17, 2010