Polymath or Matlab non-linear algebraic solver

[member 392791]

Hello,

I am having difficulty inputting a non linear algebraic equation into polymath to solve

for reference the equation is

x*(100-.5*x)^0.5/(15-x)/(20-.5 * x)^0.5 - 87.824 == 0

and I want to solve for x, but haven't gotten anything. Also I don't know how to program it into matlab. Anyone that can help?? Thank you

 

[kreil]

Try the fzero() function.
http://www.mathworks.com/help/matlab/ref/fzero.html

 

[SteamKing]

It could be that the software is having trouble parsing your equation as it is written. Don't skimp on parentheses.

 

[kreil]

Unless you explicitly want matrix power or matrix multiply, I recommend using the array operators exclusively.

fun = @(x) x.*(100-0.5.*x).^0.5./(15-x)/(20-0.5.*x).^0.5 - 87.824;

When I plotted this function, I did not find any real solutions for x. If it has any, they are complex.

 

[alphy]

I understand your frustration with trying to input a non-linear algebraic equation into a solver like Polymath or Matlab. Non-linear equations can be complex and challenging to solve, even for experienced mathematicians. One possible solution is to break the equation down into smaller, simpler parts and solve them individually using numerical methods. Another option is to seek help from a mathematician or an experienced user of the software who may be able to provide guidance on how to properly input and solve the equation. Additionally, there are online resources and forums where you can ask for assistance from other users who may have encountered similar problems. Keep in mind that solving non-linear equations often requires a combination of mathematical knowledge and programming skills, so it may take some time and effort to find a solution. Don't give up, and keep exploring different approaches until you find a successful solution.