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, FindRoot[] may help you. 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? | | Thank you in advance! |