Re: Solving

• To: mathgroup at smc.vnet.net
• Subject: [mg8281] Re: [mg8182] Solving
• From: seanross at worldnet.att.net
• Date: Sun, 24 Aug 1997 04:46:21 -0400
• Sender: owner-wri-mathgroup at wolfram.com

```Awwad A. Al-Harthi wrote:
>
> Hi there,
> I am trying to use mathematica to solve the following problems:
>
> 1. I could not get an answer when I enetred the following in mathematica
>
>         Log[1/(g+g *  Exp[x/g])]
>
> The output I get is simply my input.

What did you want mathematica to do?  If you wanted algebraic
simplification, then check out the various commands Simplify,
FullSimplify etc.
>
> 2. Given the functions:
>
>                 a. 1/(g + g * e^(x/g))
>
> how can I use mathematica to solve for x?.
Do you want numeric or symbolic solutions.  If numeric, then NSolve or
FindRoot are your best bets. If symbolic, then Solve .

and
>
>                 b. F(t) = q + p * e^(-(t+c)(q+p)) / q*{1 + e^(-(t+c)(q+p))}
>
> How can I use mathematica to solve for c if F(0) = 0 ?.

#1-to enter an expression as a "function", use :=,  ie.  F[t_]:=.....
#2-when entering equations in Solve, use == or === in your equalities.
>
> Many many thanks