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.