Re: Domain of Sin[ArcSin[x]] ?
- To: mathgroup at smc.vnet.net
- Subject: [mg39641] Re: [mg39620] Domain of Sin[ArcSin[x]] ?
- From: Sseziwa Mukasa <mukasa at jeol.com>
- Date: Thu, 27 Feb 2003 00:27:46 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
On Wednesday, February 26, 2003, at 02:42 AM, Michael Buescher wrote: > I want to demonstrate to my students that in the real number system, > Sin[ArcSin[x]] is only defined on [-1,1] because that is the domain of > ArcSin[x]. When I Plot the composition, however, I get Sin[ArcSin[x]] > = > x for all real numbers, not just on [-1,1]. I tried this both with and > without the RealOnly package. > > Is there any way to ensure that Mathematica uses only real numbers in > its calculations, so that Sin[ArcSin[x]] is undefined when ArcSin[x] is > not a real number? > > Michael Buescher > Hathaway Brown School > One possibility is to make your own ArcSin that is only valid on the interval [-1,1]. Regards, Ssezi