- #1
mathnovice
- 5
- 1
Homework Statement
divide in partial fractions:
x^3 -3x^2+x-12 / x^4+5x^2+4
Homework Equations
The Attempt at a Solution
I factored x^4+5x^2+4 to (x^2 +1) (x^2+4)
x^3 -3x^2+x-12/(x^2 +1) (x^2+4) = A (x^2+1)/(x^2 +1) (x^2+4) + B (x^2+4) /(x^2 +1) (x^2+4)
they all have the same denominator so: x^3-3x^2+x-12 = A (x^2+1) + B (x^2+4)
now normally my next step would be to try to solve for A by making ( x^2+4) equal to zero so I don't have B in my equation anymore. so I should find an x where x^2 is -4 but this is impossible because of the ^2. how do I solve this? thanks in advance