# Laurent series

• September 11th 2011, 01:04 AM
capea
Laurent series
$\frac{-1}{\sqrt{x+1}}$ how is it possible calculate the residue bout x=-1 and do the laurent series about of x=-1 thanks,
• September 11th 2011, 01:10 AM
chisigma
Re: Laurent series
Quote:

Originally Posted by capea
$\frac{-1}{\sqrt{x+1}}$ how is it possible calculate the residue bout x=-1 and do the laurent series about of x=-1 thanks,

Unfortunately the function $f(z)=- \frac{1}{\sqrt{1+z}}$ has in z=-1 a brantch point, so that the Laurent series around z=-1 doesn't exist...

Kind regards

$\chi$ $\sigma$