Re: Solving Equations with 3 variables and many parameters
- To: mathgroup at smc.vnet.net
- Subject: [mg132379] Re: Solving Equations with 3 variables and many parameters
- From: Bob Hanlon <hanlonr357 at gmail.com>
- Date: Sun, 2 Mar 2014 21:26:14 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- Delivered-to: l-mathgroup@wolfram.com
- Delivered-to: mathgroup-outx@smc.vnet.net
- Delivered-to: mathgroup-newsendx@smc.vnet.net
- References: <20140302060452.5EAEC69E6@smc.vnet.net>
You need to use Equal ( == ) in the equations rather than Set ( = ). eqns1 = {P1 == (a[1] + C*b[11] + b[12]*P2)/(2*b[11]), P2 == (a[2] + C*b[22] + b[21]*P1)/(2*b[22])}; sol1 = Solve[eqns1, {P1, P2}]; eqns1 /. sol1 // Simplify {{True, True}} eqns2 = {P1 == (a[1] + C*b[11] + b[12]*P2 + b[13]*P3)/(2*b[11]), P2 == (a[2] + C*b[22] + b[21]*P1 + b[23]*P3)/(2*b[22]), P3 == (a[3] + C*b[33] + b[31]*P1 + b[32]*P2)/(2*b[33])}; sol2 = Solve[eqns2, {P1, P2, P3}]; eqns2 /. sol2 // Simplify {{True, True, True}} Bob Hanlon On Sun, Mar 2, 2014 at 1:04 AM, drascher <rascher at usfca.edu> wrote: > Hello, > > I am able to get Mathematica to solve: > > Solve[{P1=(a[1]+C*b[11]+b[12]*P2)/(2*b[11]), > P2=(a[2]+C*b[22]+b[21]*P1)/(2*b[22])}, {P1, P2}] > > but it won't solve the following (which is one more variable P3 and its > equation): > > Solve[{P1=(a[1]+C*b[11]+b[12]*P2+b[13]*P3)/(2*b[11]), > P2=(a[2]+C*b[22]+b[21]*P1+b[23]*P3)/(2*b[22]), > P3=(a[3]+C*b[33]+b[31]*P1+b[32]*P2)/(2*b[33])}, {P1, P2, P3}] > > It says that it doesn't understand how to interpret the word "Solve" even > though it does it for the first eqn. > > Any help is appreciated. > >
- References:
- Solving Equations with 3 variables and many parameters
- From: drascher <rascher@usfca.edu>
- Solving Equations with 3 variables and many parameters