sin(72 degrees) not evaluated



> From: Fibonacci Prower
> Sent: Monday, 22 May 2006 13:21
> To: maxima at math.utexas.edu
> Subject: sin(72 degrees) not evaluated
> 
> 
> Hello all,
> 
> I have very recently installed Maxima, and am learning to use it. I
> have just discovered that cos(%pi/5) is not evaluated to its algebraic
> value, which would be (sqrt(5)+1)/4; instead, it generates an output
> identical to the input. On the other hand, cos(%pi/4) is evaluated to
> its well-known value of sqrt(2)/2.
>
> What am I doing wrong?

You need the ntrig share package.  It is mentioned in the manual.

(%i1) cos(%pi/5);

				       %pi
(%o1) 			   cos(---)
					5
(%i2) load('ntrig)$
(%i3) cos(%pi/5);
				  sqrt(5) + 1
(%o3) 			  -----------
				       4
(%i4)


NOTICE
This e-mail and any attachments are private and confidential and may contain privileged information. If you are not an authorised recipient, the copying or distribution of this e-mail and any attachments is prohibited and you must not read, print or act in reliance on this e-mail or attachments.
This notice should not be removed.