Let,s suppose we have the next integral:(adsbygoogle = window.adsbygoogle || []).push({});

[tex]\int_{c-i\infty}^{c+i\infty}dsF(s)e^{sx} [/tex]

with c a real number..of course F(s) is so complicated that we can not evaluate it... first of all we make the change of variable s=c+iu so we would get the "new" integral:

[tex]\int_{-\infty}^{\infty}iduF(c+iu)e^{iux+cx} [/tex] being this a Fourier transform..my question is supposing x---->oo (infinity) ¿How could we evaluate it by a "Saddle point" method or other form similar to the one Laplace did to calculate the factorial?..thanks in advance.

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# Asymptotic expansion of complex integrals?

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