[Date Index]
[Thread Index]
[Author Index]
Re: Exact value of Cos[Pi/17]
*To*: mathgroup at smc.vnet.net
*Subject*: [mg14851] Re: Exact value of Cos[Pi/17]
*From*: "Allan Hayes" <hay at haystack.demon.co.uk>
*Date*: Fri, 20 Nov 1998 02:16:59 -0500
*References*: <72tt9f$isg@smc.vnet.net>
*Sender*: owner-wri-mathgroup at wolfram.com
Christopher Gorski wrote in message <72tt9f$isg at smc.vnet.net>...
>In The Mathematica Book, there is an example on page 936 of Mathematica
>returning the exact answer to Cos[Pi/17]. When I try it out on my NT
>machine, however, (mathematica v.3), it simply returns Cos[Pi/17].
>I've searched throughout the book, and I can't figure out how to get my
>system to return a answer as in the example given. It will return
>simple things, Cos[Pi], for example, returns -1, but more complex
>arguments won't work.
>
>--
>Christopher Gorski
>cgorski at adelphia.net
>http://www.contrib.andrew.cmu.edu/~cgorski
>
>
>
Christopher (using InputForm for Output cells)
Cos[Pi/17]
Cos[Pi/17]
FunctionExpand[%]
1/4*Sqrt[1/2*(15 + Sqrt[17] + Sqrt[2*(17 - Sqrt[17])] +
Sqrt[2*(34 + 6*Sqrt[17] - Sqrt[2*(17 - Sqrt[17])] +
Sqrt[34*(17 - Sqrt[17])] -
8*Sqrt[2*(17 + Sqrt[17])])])]
?FunctionExpand
"FunctionExpand[expr] tries to expand out special and certain other
functions \
in expr, when possible reducing compound arguments to simpler ones. \
FunctionExpand[expr, assum] expands using assumptions."
Allan
Prev by Date:
**Evaluation Control**
Next by Date:
**Bug in NonlinearRegress on NDSolve**
Previous by thread:
**Exact value of Cos[Pi/17]**
Next by thread:
**Re: Exact value of Cos[Pi/17]**
| |