# Evaluation Of Real Integrals By Contour Integration

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**Evaluation of Real Integrals by Contour Integration:**

For such questions consider a unit radius circle with center at origin, as contour

Now use following relations

We get, the whole function is converted into a function of f (z), Now integral become

where C is unit circle. The value of this integral may be obtained by using Residue Theorem, which is 2πi.(Sum of Residue inside C)

**Form I:**

**Examples:** Use residue calculus to evaluate the following integral

**Solutions:
**

Poles of integrand are given by

Hence by Cauchy’s Residue Theorem