Partial Fraction Decomposition Math Example 4

Follow the full solution, then compare it with the other examples linked below.

Example 4

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Integrate โˆซ1x2โˆ’4โ€‰dx\displaystyle\int \frac{1}{x^2-4}\,dx.

Solution

  1. 1
    (xโˆ’2)(x+2)(x-2)(x+2): A/(xโˆ’2)+B/(x+2)A/(x-2)+B/(x+2). A=1/4A=1/4, B=โˆ’1/4B=-1/4.
  2. 2
    14lnโกโˆฃxโˆ’2โˆฃโˆ’14lnโกโˆฃx+2โˆฃ+C=14lnโกโˆฃxโˆ’2x+2โˆฃ+C\frac{1}{4}\ln|x-2|-\frac{1}{4}\ln|x+2|+C = \frac{1}{4}\ln\left|\frac{x-2}{x+2}\right|+C.

Answer

14lnโกโˆฃxโˆ’2x+2โˆฃ+C\frac{1}{4}\ln\left|\frac{x-2}{x+2}\right| + C
Factor the difference of squares, apply partial fractions, integrate logarithmically.

About Partial Fraction Decomposition

Breaking a rational expression into a sum of simpler fractions whose denominators are the factors of the original denominator.

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