What is the mistake in my calculation of $\int_0^\infty {\cos(ax)\over(x^2+1)^2}dx$?
8432
Computing real integral using residues
90095
Integrate $\int_0^{\infty } \frac{\cos x}{x} dx$
136602
Why is $\int_1^{\infty}(1/x^2)\,dx$  less than $\sum_{n=1}^{\infty} 1/(n^2)$?
62109
$\int_{-\infty}^{\infty} \frac{\cos(αx)}{(x^2+1)(x^2+4)} \mathrm dx$ using Complex methods
158147
Calculating $\int_{-\infty}^{\infty}\frac{\sin(ax)}{x}\, dx$ using complex analysis
148826
Integral of $ 1 \, / \, (1 + a \, \cos(x) )$
123694
How to compute the integral $\int_{0}^{\infty} \frac{x^{1/3}}{1+x^{2}} \ dx$
137648
What is the mistake in doing integration by this method?
145590
Compute the integral $\int\frac{dx}{(x^2-x+1)\sqrt{x^2+x+1}}$
43484
Integration by parts: $\int e^{ax}\cos(bx)\,dx$
95426
How to compute $ \frac{1}{\sqrt{2\pi}} \int_{-\infty}^\infty \frac{e^{-{x^2}/{2}}}{1+e^{-(ax+b)}}\,\mathrm dx $ when $b \ne 0$
140638
Integrating $\int_0^{\infty} \frac{dx}{1+x^3}$ using residues.
8705
Evaluation of $\sum_{x=0}^\infty e^{-x^2}$
51991
What is the integral of $e^{\cos x}$
101587
Calculating $\int_{- \infty}^{\infty} \frac{\sin x \,dx}{x+i} $
29546
Residue integral: $\int_{- \infty}^{+ \infty} \frac{e^{ax}}{1+e^x} dx$ with $0 \lt a \lt 1$.
31964
Evaluating $\int_0^{\infty}\frac{\ln(x^2+1)}{x^2+1}dx$