Re: Sin[30*Degree] vs Sin[29*Degree]
- To: mathgroup at smc.vnet.net
- Subject: [mg72090] Re: Sin[30*Degree] vs Sin[29*Degree]
- From: Heiko Damerau <heiko.damerau.news at cern.ch>
- Date: Mon, 11 Dec 2006 04:55:26 -0500 (EST)
- Organization: CERN News
- References: <elglnb$h7f$1@smc.vnet.net>
Dear Steven,
The behaviour of Mathematica is perfectly consistent. It depends on
whether you look for an exact or for a numerical result.
Sin[30*Degree] is indeed 1/2 and this result is exact. However, for
Sin[29*Degree] or Sin[31*Degree] Mathematica cannot find any exact
solution and just keeps the expression unevaluated. If you want the
numerical result, ask e.g. for N[Sin[29*Degree]]. By typing
Sin[29*Pi/180.] you are asking for the numerical result as 180. <- with
a dot at the end means the numerical value 180 and Mathematica will
automatically perform a numerical calculation. Try to ask Mathematica
for the exact result of Sin[29*Pi/180] and you will see that the
expression is kept as well as Sin[29*Degree]. Again, this time
Mathematica tries to find the exact solution... which doesn't exist.
Hope this helps,
Heiko
Steven Shippee schrieb:
> What is happening here:
>
> Sin[30*Degree]
> Sin[31*Degree]
> Sin[29*Degree]
> which makes it appear that only the first line of input works?
>
> However, if I do something like:
>
> \!\(Sin[\(29*Pi\)\/180. ]\)
>
> I get the expected result ... I'm sure it is me, what am I missing in that I
> think I am not seeing consistent behavior?
>
> Thanks in advance,
>
> Steven Shippee
>
> slshippee at comcast.net
>
>
>
>