How do you express x/((x-1)(x^2+4)x(x1)(x2+4) in partial fractions?

1 Answer
Nov 7, 2016

The answer is x/((x-1)(x^2+4))=1/(5(x-1))+(-x+4)/(5(x^2+4))x(x1)(x2+4)=15(x1)+x+45(x2+4)

Explanation:

Let x/((x-1)(x^2+4))=A/(x-1)+(Bx+C)/(x^2+4)x(x1)(x2+4)=Ax1+Bx+Cx2+4
=(A(x^2+4)+(Bx+C)(x-1))/((x-1)(x^2+4))=A(x2+4)+(Bx+C)(x1)(x1)(x2+4)
So x=A(x^2+4)+(Bx+C)(x-1)x=A(x2+4)+(Bx+C)(x1)
if x=0x=0 =>0=4A-C0=4AC
coefficients of x^2x2 =>0=A+B0=A+B
coefficents of xx => 1=-B+C1=B+C
Solving for A,B, CA,B,C
A=1/5A=15
B=-1/5B=15
C=4/5C=45

:.x/((x-1)(x^2+4))=1/(5(x-1))+(-x+4)/(5(x^2+4))