Using Complex contour integration calculate ∫∞−∞sinxx+idx . Use the form ∫∞−∞f(x)sin(αx)dx
Now I used the form ∫∞−∞f(x)sin(αx)dx and converted the integral to Img(∮∞−∞eixx+idx) where the contour is the positive semi-circle around the origin from [−R,R] as R→∞
But then the only pole of the above integral is x=−i, which is not in the above contour hence the value of the integral in the above contour is zero thus the value of the integral is zero . But the answer given in the text is not so
Could someone please calculate this integral
Answer
Hint: ∫∞−∞sinxx+idx=∫∞−∞xsinxx2+1dx−i∫∞−∞sinxx2+1dx
and you can easily apply Jordan's lemma on these guys and calculate the integrals from residue theorem.
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