Re: Simple question from a biologist

• To: mathgroup at smc.vnet.net
• Subject: [mg67152] Re: Simple question from a biologist
• From: Helen Read <hpr at together.net>
• Date: Sun, 11 Jun 2006 02:16:59 -0400 (EDT)
• References: <e6e27d\$1tp\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```tnad wrote:
> I'm a bit new to this so please bear with me. I solved this eqation:
>
> Sol = Solve[{{{-x, 0, z}, {x, -y, 0}, {0, y, -z}}.{A, B, C} == 0, A + B + C == 1}, {A, B, C}]
>
> and got the ouputs of A, B and C interms of x,y, and z each.
>
> Now I want to express a term called "rate" where rate = Ax = By = Cz in terms of x, y and Z only.
>
> So I tried to do this:
> Solve[rate == Ax , rate] /. Sol
>
> but I cannot get the rate in terms of x,y and z.

"Ax" is a new symbol. If you mean A times x, put a space between A and x.

Solve[rate==A x,rate]/.Sol

works fine.

Solve is unecessary, however, since all you are doing is evaluating an
expression.

Why not simply:

A x/.Sol

or better yet:

rate = A x /. Sol[[1]]

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