Solving a nonlinear, nonpolynomial system of equations  SOLVED

05052019, 07:38 PM
(This post was last modified: 05052019 08:33 PM by rrpalma.)
Post: #1




Solving a nonlinear, nonpolynomial system of equations  SOLVED
Hello,
I'm in the process of familiarizing myself with my new Prime. I'm very familiar with the HP42/DM42 and especially with the HP50G. I think the Prime is an extremely powerful calculator, and am enjoying the learning curve. It amazes me how fast it is, and if I go back to the 50G, I find myself continuously tapping at its screen :) However, I'm still confused about how to do certain things on the Prime, one of them being solving multiple nonlinear equations. Let's suppose I have the following system: (X/Y)^Z = 1/8 2^X/3^Y=4/Z^4 X*Y/Z=8/3 On the HP50g, I just use the equation writer to place all 3 equations on the stack, then create an array with them. I then create an array with [X Y Z] and another with my initial guesses [1 1 1]. I go to NUM.SLV>MSLV and then get an array with 2, 4 and 3 as the answers. On the Prime, I go into CAS mode, then I define: EQ1:=((x/y)^z) = 1/8 EQ2:=(2^x/3^y) = 4/z^4 EQ3:=(x*y/z) = 8/3 Then I type: L0:=solve({EQ1,EQ2,EQ3},{x,y,z}) And I get the following error: {"[x,2^x] is not rational w.r.t. x Error: Bad Argument Value"} What am I doing wrong? Thanks for reading!! EDIT === OK, I found what I was doing wrong!! I forgot to provide the guesses. My mistake; my apologies for asking dumb questions. Got it to work with: L0:=solve({EQ1,EQ2,EQ3},{x,y,z},{1,1,1}) Moderators: please delete this post.... 

05052019, 11:10 PM
Post: #2




RE: Solving a nonlinear, nonpolynomial system of equations  SOLVED
(05052019 07:38 PM)rrpalma Wrote: Moderators: please delete this post.... Nah... leave it here; you're answer will help someone in the future looking for info about the same problem. So thanks for posting the answer you found for yourself; most folks simply don't come back to update the question with the answer. Bob Prosperi 

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