$\displaystyle \frac{z-\sin z}{z^4}$

my singular point is 0

if i will do lhopital 4 times on the lmit i will get -sin z/6 =0

which is singular point because the result is constant

so why its a first order pole?

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- Jul 12th 2010, 10:12 AMtransgalacticwhy its not removable singular point??
$\displaystyle \frac{z-\sin z}{z^4}$

my singular point is 0

if i will do lhopital 4 times on the lmit i will get -sin z/6 =0

which is singular point because the result is constant

so why its a first order pole? - Jul 12th 2010, 10:21 AMJose27
- Jul 12th 2010, 10:19 PMtransgalactic
ok now i tried to determine the power of the pole

i did

g(x)=1/f(x)

where x=0

and i got that g'(0)=0/0 which means that its not a first order pole

actualyy i should get zero but i got 0/0

?? - Jul 13th 2010, 03:31 AMmr fantastic
- Jul 13th 2010, 04:12 AMtransgalactic
i want to solve it by the derivative way

not by developing into a series - Jul 13th 2010, 04:57 AMmr fantastic