       Re: Solving equations involving Ln function

• To: mathgroup at smc.vnet.net
• Subject: [mg19905] Re: Solving equations involving Ln function
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Tue, 21 Sep 1999 02:22:43 -0400
• Organization: Universitaet Leipzig
• References: <7s1pb3\$9n9@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Hi,

Mathematica need a bit help:

eqn = Log[x] + delta*v ==
Log[(1 - delta)*x/(1 - delta^2)] +
delta*Log[(1 - delta)*delta*x/(1 - delta^2)] + delta^2*v

eqn1 = eqn /. a_ == b_ :> a - b == 0 //.
a_.Log[b_] + c_.Log[d_] :> Log[b^a*d^c] /.
a_ + Log[b_] == 0 :> Exp[a] == -b

and you get:

Solve[eqn1, x]

Hope that helps
Jens

Satyajit Bose wrote:
>
> Hello,
>
> I am trying to solve some equations involving the natural log function.

SNIP SNAPP

Here is
> my input line and results in the kernel:
>
> In:=
> Solve[Log[x]+delta*v==Log[(1-delta)*x/(1-delta^2)]+delta*Log[(1-delta)*d
>
> elta*x/(1-delta^2)]+delta^2*v,x]
>
> Solve::tdep: The equations appear to involve transcendental functions of
> the
>     variables in an essentially non-algebraic way.

SNIP SNAPP

> I am hoping to get a solution that looks like this:
>
> x -> exp[v*(1-delta)]*(1+delta)^(1+1/delta)/delta)
>
> Thank you for all your  help.
>
> Sayajit Bose

```

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