title: how to use fsolve without starting guess
body: <p>I want to develop a desktop application for solving system of linear and nonlinear equations.
  I am thinking to use C# with Matlab. I never use matlab before but i am trying to learn for my project.</p>
  
  <p>So, I am trying to use fsolve and i follow the example given on documentation of fsolve.</p>
  
  <pre><code>function F = myfun(x)
  F = [2*x(1) - x(2) - exp(-x(1));
      -x(1) + 2*x(2) - exp(-x(2))];
  
  **x0 = [-5; -5];           % Make a starting guess at the solution**
  options=optimset('Display','iter');   % Option to display output
  [x,fval] = fsolve(@myfun,x0,options)  % Call solver
  </code></pre>
  
  <p>Here in my case i don't know the starting guess i.e. x0</p>
  
  <p>I just have n number of equation with n unknown. Please guide me what to do and how to proceed. </p>
  
  <p>Some sample equations: </p>
  
  <pre><code>a * b = 10^-14
  (a * d)/c = 10^-6.3
  (a * e)/d = 10^-10.3
  .
  .
  .
  c+d+e = 2.3 * 10^-3
  </code></pre>