How do I change tolerance for fsolve() ?

Hi, I have a code snippet like this:

 options = optimset('Display','iter');
 options = optimset(options,'display','on');
 [x]= fsolve(@main_mod,temp_mat(:,cntr),options);

where:

cntr: counter

temp_mat: holds temperature of plates from previous iteration (used as starting guess for next iteration)

The equations formed under function mainmod are 6 equations all in their fourth power and I use symbolic variables. (all 6 variables that are to be determined by solving the equations, simultaneously.

Problem is: fslove says: No solution exists. The purpose of the code is to determine temperature of 6 plates. Thus a solution must exist (yes?)

Anybody can please help me out?

Thanks, Riddle!

[Walter Roberson]

We will probably need to see your code.