Resolution of systems of equation

hi,

i try to resolve a system of equation using 'solve' function, then i use 'eval' to have numerical result, i get four result but one of them it verify my condition, how can i choose automatycly the true result?,

this is the simulation in the work space, but when i use the matlab function bloc to developp my program i have mistake to use feval with multiple symbolique expression had from solve.

can u help me?

Answer 1

[Walter Roberson]

With the information you have given, it is not possible to automatically choose the "true result".

If we had the expression, and if we were told the valid ranges for all of the variables in the expression, and if we were told how to recognize a "true result", then there is a possibility that we might be able to come up with a solution.

If the restriction is that the results should be real-valued, then it might be possible to invoke solve() to give a real-valued solution.

In your earlier postings, you had expressions with four solutions, two of which were complex-valued and two were real-valued. What you wrote then was consistent with the possibility that you wanted the real-valued positive solution, but you did not clarify that when asked. For example you might have wanted the larger solution. Or the one with the greatest absolute magnitude.