Re: Usage of #1
- To: mathgroup at smc.vnet.net
- Subject: [mg96294] Re: [mg96273] Usage of #1
- From: "David Park" <djmpark at comcast.net>
- Date: Wed, 11 Feb 2009 05:18:45 -0500 (EST)
- References: <22848050.1234263649880.JavaMail.root@m02>
Nandhini, The reason Mathematica returns a Root expression is that it is an EXACT representation of a root of a polynomial equation. (Just as Pi and Sqrt[2] are exact representations of the respective numbers.) Often, Mathematica can do further combinations or simplifications and stay with the exact numbers. #1 stands for the variable of the polynomial and 1+a #1+a^2 #1^5 & is a pure function that represents the polynomial. Look up Function and Root in Help. In this case the polynomial has a parameter, a. You can evaluate the Root to an approximate number by replacing a with a number and then using N on the expression. (% stands for the output of the previous line.) Root[1+a #1+a^2 #1^5&,1] %/.a->2 N[%] giving Root[1 + a #1 + a^2 #1^5 &, 1] Root[1 + 2 #1 + 4 #1^5 &, 1] -0.459175 David Park djmpark at comcast.net http://home.comcast.net/~djmpark/ From: Nandhini [mailto:nandhini.gopalan at gmail.com] Frnds, Im very new to mathematica. I have got a result where im getting something like "Root[1+a #1+a^2 #1^5 &,1]. i wud like to know how else i can write it. i dont want the #1 to b displayed. is tehre any alternative. Plz help me out of this. Thanks in advance, Nandhini