Re: solving an equation with sums

• To: mathgroup at smc.vnet.net
• Subject: [mg67487] Re: solving an equation with sums
• From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
• Date: Wed, 28 Jun 2006 03:51:36 -0400 (EDT)
• Organization: Uni Leipzig
• References: <e7qmi0\$6lb\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Hi,

Regards
Jens

<newbix at bk.ru> schrieb im Newsbeitrag
news:e7qmi0\$6lb\$1 at smc.vnet.net...
| Hello,
|
| I try to solve the following equation:
|
sum[2*(1-e^(-x*t[[i]])-F[[i]])*t[[i]]*e^(-x*t[[i]]),{i,1,10}]==0
| where t and F are lists. Each list has ten
entries.
| I tried to solve this sum using the following
command:
| ------------------------------------------------------
| Solve[2*(1 - \[ExponentialE]^(-x*0.1) -
2810)*0.1*\[ExponentialE]^(-x*0.1) +
|      2*(1 - \[ExponentialE]^(-x*0.2) -
5411)*0.2*\[ExponentialE]^(-x*0.2) +
|      2*(1 - \[ExponentialE]^(-x*0.3) -
8701)*0.3*\[ExponentialE]^(-x*0.3) +
|      2*(1 - \[ExponentialE]^(-x*0.4) -
13130)*0.4*\[ExponentialE]^(-x*0.4) +
|      2*(1 - \[ExponentialE]^(-x*0.5) -
17327)*0.5*\[ExponentialE]^(-x*0.5) +
|      2*(1 - \[ExponentialE]^(-x*0.6) -
24899)*0.6*\[ExponentialE]^(-x*0.6) +
|      2*(1 - \[ExponentialE]^(-x*0.7) -
31230)*0.7*\[ExponentialE]^(-x*0.7) +
|      2*(1 - \[ExponentialE]^(-x*0.7) -
40006)*0.8*\[ExponentialE]^(-x*0.8) +
|      2*(1 - \[ExponentialE]^(-x*0.8) -
59880)*0.9*\[ExponentialE]^(-x*0.9) +
|      2*(1 - \[ExponentialE]^(-x) -
80017)*\[ExponentialE]^(-x) == 0, x]
| -----------------------------------------
| but I got the following error message:
|
| Solve::"tdep": "The equations appear to involve
the variables to be solved \
| for in an essentially non-algebraic way."
|
| What's wrong? How can I solve this expression
using Mathematica?
|