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Re: Solving log equations, how?

• To: mathgroup at smc.vnet.net
• Subject: [mg13635] Re: Solving log equations, how?
• From: Arnoud Buzing <arnoudb>
• Date: Thu, 06 Aug 1998 16:41:33 -0500
• Organization: Wolfram Research, Inc.
• References: <6qcqvq$qln$4@dragonfly.wolfram.com>
• Sender: owner-wri-mathgroup at wolfram.com

Jeffrey A. Soesbergen wrote:
> 
> How can I solve the following exponential equations:
> 
> 1. log3 x=-2
> 
> 2. log x + log (x+3) = 1
> 
> Can anyone tell me how to solve these in Mathematica?

You can solve equations in Mathematica with the Solve[] command. It
takes two arguments: the equation you want to solve and the variable
you want to solve for. In your case the expressions to evaluate are:

Solve[Log[3 x] == -2, x] (followed by shift-enter)

Solve[Log[x] + Log[x + 3] == 1, x] (followed by shift-enter)

You need to use == instead of = to indicate equality; the = is used for
assignment.

---
Arnoud