Integration of Rational functions: Example1

Find
Solution. Since the degree of the numerator is higher than the denominator, we should perform the long-division. We get
which implies
We concentrate on the fraction
. The partial
decomposition technique gives
This gives x + 2 = A(x-1) + B(x+1). If we substitute x=1, we get B = 3/2 and we substitute x=-1, we get A = -1/2. Therefore, we have
Now we are in position to perform the desired integration. Indeed, we have
Since we have
,
we get

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Author: Mohamed Amine Khamsi