Re: Series expansion of ArcSin around 1
- To: mathgroup at smc.vnet.net
- Subject: [mg21628] Re: [mg21598] Series expansion of ArcSin around 1
- From: Hugh Walker <hwalker at gvtc.com>
- Date: Tue, 18 Jan 2000 02:35:15 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
>Hi!
>
>I have the following problem. My x is close to 1 but sligthly
>smaller. I want to expand ArcSin[x] around 1 but this is what I get:
>
>In[53]:= Series[ArcSin[x],{x,1,4}]
>
> I 3/2 3 I 5/2
> - (-1 + x) --- (-1 + x)
> Pi 6 80
>Out[53]= -- - I Sqrt[2] Sqrt[-1 + x] + ------------- - --------------- +
> 2 Sqrt[2] Sqrt[2]
>
> 5 I 7/2
> --- (-1 + x)
> 448 9/2
>> --------------- + O[-1 + x]
> Sqrt[2]
>
>How to tell Mathematica that my x is real and smaller than 1
>so it will not return all this complex numbers?
>
>Thanks for any help,
>
==========
This works OK:
Series[ArcSin[1 - q], {q, 0, 3}]
==
Hugh Walker
Gnarly Oaks