- #1
anniecvc
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Homework Statement
∫10x-2x2/((x-1)2(x+3))
Solve by partial fractions.
The Attempt at a Solution
∫A/(x-1) +B/(x-1)2 + C(x+3)
after setting up the partial fractions and multiplying each term by LCD:
10x-2x2= A(x-1)(x+3) + B(x+3) + C(x-1)2
10x-2x2= A(x2+2x-3) +Bx+3B +Cx-C
10x-2x2= Ax2+2Ax-3A+Bx+3B+Cx-C
10x-2x2= x2(A+C) +x(2A+B-2C) + (3B+C-3A)
System of Equations:
A+C = -2
2A+B-2C=10
3B+C-3A =0
Solving these, I get A=23. B=14. C=25.
Putting them back in their partial fractions form and integrating I get:
23*lnlx-1l - 14/(x-1) + 25*lnlx+3l
However Wolfram gives me essentially the same terms but different coefficients: http://www.wolframalpha.com/input/?i=integral+of+%2810x-2x%5E2%29%2F%28%28x-1%29%5E2*%28x%2B3%29%29
What am I doing wrong?