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Re: What the meant of the symbols # and & on the following example

• To: mathgroup at smc.vnet.net
• Subject: [mg129624] Re: What the meant of the symbols # and & on the following example
• From: svkeeley at aol.com
• Date: Wed, 30 Jan 2013 22:06:12 -0500 (EST)
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• References: <ke7uh6$4i0$1@smc.vnet.net>

On Monday, January 28, 2013 11:42:30 PM UTC-8, Chris wrote:
> Bellow is presented an eigenvalue resultant of a jacobian matrix...  where appears (..)#1 and (..)#1^2,& what it means?
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> Root[C0 CG^2 vG^2 vL  \+(2 C0 CL^2 vG vL \[Alpha]^2 \[Rho]L^2+C0 CL^2 vL^2 \[Alpha]^2 \[Rho]L^2) #1+([Alpha] \[Rho]L^2-C0 CL^2 vG \[Alpha]^2 \[Rho]L^2-2 C0 CL^2 vL \[Alpha]^2 \[Rho]L^2) #1^2&,1]
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> best regards

This is what Mathematica calls a pure function.  The # represents a variable. #1 is one variable, #2 would be another.  In your result, #1 is one new variable Mathematic added. #1^2 is that variable squared. The & is just a sign that the preceding is a pure function.

For example, you could write a function lixe this:

f[x]:= x^2

or you could write it as a pure function:

f=#^2&

Either way, f[3] would give you an answer of 9, and f[x+y] would return (x+y)^2.