Evaluate the following integral:

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Multiply numerator and denominator by xn – 1, we get
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Let xn = t ⇒ nxn – 1dx = dt
So the above equation becomes,
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The denominator is factorized, so let separate the fraction through partial fraction, hence let
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⇒ 1 = A(t + 1) + Bt……(ii)
Put t = 0 in above equations we get
1 = A(0 + 1) + B(0)
⇒ A = 1
Now put t = – 1 in equation (ii) we get
1 = A( – 1 + 1) + B( – 1)
⇒ B = – 1
We put the values of A and B values back into our partial fractions in equation (i) and replace this as the integrand. We get
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Split up the integral,
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Let substitute
u = t + 1 ⇒ du = dt, so the above equation becomes,
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On integrating we get
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Substituting back the values of u, we get
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Substituting back the values of t, we get
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Applying the logarithm rules, we get
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Note: the absolute value signs account for the domain of the natural log function (x>0).
Hence,
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