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