Thread: Partial fraction

1/x^2/(x^2+4);

I tried:
A/x^2 + B/(x^2+4) + (cx+d)

1 = (x^2+4)*A+x^2*B+(cx+d)/x^2/(x^2+4)

Now I tried to put each to equal 0...


I still don't know how to get to the solution which is supposed to be:
-1/(4*(x^2+4))+1/(4*x^2)

Originally Posted by LightEight

1/x^2/(x^2+4);

I tried:
A/x^2 + B/(x^2+4) + (cx+d)

1 = (x^2+4)*A+x^2*B+(cx+d)/x^2/(x^2+4)

Now I tried to put each to equal 0...


I still don't know how to get to the solution which is supposed to be:
-1/(4*(x^2+4))+1/(4*x^2)

When you break down the fraction, you need to find numerators of degree one less than the denominators. So for x^2 terms like you have you need to find (Ax+B)/x^2, not A/x^2.

Try again. Here's a helpful link to remind you of the rules.

Pauls Online Notes : Calculus II - Partial Fractions

(Ax+B)/x^2+C/(x+2)+(Dx+E)/(x+2)^2-1/4*F/x

Is that correct?

I give up