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Not a quantified system of equations and inequalities

Posted 2 years ago

Can someone please help me why I'm recieving this error. I am very new to Mathematica (just started yesterday), but I can do the calculation by hand why can't mathematica? I'm trying to solve the two equations R1 and R2 for P1 and P2. Maybe I'm just being dumb lol. Here is a screen dump: enter image description here

3 Replies
Posted 2 years ago

Something like this with some specific values for A, c1, b, k and varying m. The specific values are scoped to the With.

With[{vals = {A -> 1, c1 -> 2, b -> 1, k -> 1}},
 eqns = {P1, P2} /. First@Eq /. vals;
 Plot[eqns, {m, 0, 1}, PlotLegends -> "Expressions"]]

enter image description here

POSTED BY: Rohit Namjoshi
Posted 2 years ago

Please post code that can be copied/pasted and evaluated to reproduce the problem.

Check the documentation for Solve. There are too many { }. Perhaps you mean this?

Solve[{R1 == (A + b c + k P2)/(2 b), R2 == m P1}, {P1, P2}]
(* {{P1 -> R2/m, P2 -> (-A - b c + 2 b R1)/k}} *)
POSTED BY: Rohit Namjoshi

Hi, i kinda figured it out. I think my code is pretty bad though. I will attach my Notebook, maybe you can come with some helpful tips. I further want to plug in values for my constants in order to graph my spesific problem, but do not know how to do this without ruining my general solution for the model.

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