MATLAB: Solving a set of transcendental equations syntax error

fzeroMATLABSymbolic Math Toolbox

I have a set of geometric relationships where the independent variable is the angle theta and the dependent variable s2 is given by the following code. I am attempting to use code to write my anonymous function for fzero but I get an error message "Undefined function or method 'eq' for input arguments of type 'function_handle'" Any suggestions? Thank you, Scott
function s2_function(theta)
% =========================================================================

% system constants & initial values
  P0 = [0,0];                 
  p1 = [6,2];                             
  P4 = [18,15];               
  r1 = 4;                     
  r2 = 4;                          
  r4 = 10;                   
  s1 = sqrt((P0(1)-p1(1))^2 + (P0(2)-p1(2))^2);
  s4 = sqrt((P4(1)-p1(1))^2 + (P4(2)-p1(2))^2);
  bd = 19.65585;           
  Lb = bd*pi;                 
beta = 0.2662517;             
theta = theta*pi/180;          
%%=========================================================================


% variables solved directly
   P1 = P0 + [s1*cos(theta), s1*sin(theta)];
alpha1 = theta-beta;                        
alpha2 = asin((P4(2)-P1(2))/s4)-alpha1;     
gamma2 = asin((r1+r4)/s4);                             
   T3 = P1 + [r1*sin(gamma2-alpha2-alpha1),r1*cos(gamma2-alpha2-alpha1)];
   T4 = P4 - [r4*sin(gamma2-alpha2-alpha1),r4*cos(gamma2-alpha2-alpha1)];
%%=========================================================================
% variables solved indirectly
   syms s2 
   P2 = P1 + [s2*cos(alpha1),s2*sin(alpha1)]; 
gamma1 = asin((r1-r2)/s2);    
     x1 = gamma1 + alpha1;
     T1 = P1 + [r1*sin(x1), -r1*cos(x1)];
     T2 = P2 + [r2*sin(x1), -r2*cos(x1)];   
    [M] = CircleIntersect(P4,r4,P2,r2);
     T5 = M(1,:);
     T6 = M(2,:);
     l1 = sqrt((T1(1)-T2(1))^2 + (T1(2)-T2(2))^2);
     l2 = r1*((2*pi)- acos(1-(((T1(1)-T3(1))^2 + (T1(2)-T3(2))^2)/(2*r1^2))));
     l3 = sqrt((T3(1)-T4(1))^2 + (T3(2)-T4(2))^2);
     l4 = ArcLength(T4,T5,r4);
     l5 = ArcLength(T5,T6,r2);
     l6 = ArcLength(T6,T2,r2);
%%=========================================================================
% Solve the system of equations
  fs2 = Lb-l1-l2-l3-l4-l5-l6;
  ss2 = char(fs2);
 fhs2 = strcat('@(s2)',ss2);
   S2 = fzero(fhs2,16);
  sprintf('s2 equals: %d',S2)
   end
function [M]=CircleIntersect(P1,r1,P2,r2)
      dx = P2(1)-P1(1);                    
      dy = P2(2)-P1(2);                
   alpha = atan(dy/dx);
       s = sqrt((P1(1)-P2(1))^2 + (P1(2)-P2(2))^2);
       x = (s^2-r1^2-r2^2)/(2*r1*r2);
       y = r2/r1;
alpha2 = atan((1-x^2)^(1/2)/(x+y));
alpha1 = asin(y*sin(alpha2));
gamma1 = alpha - alpha1;
gamma2 = alpha + alpha1;
% =========================================================================
% Define intersecting points (T1 & T2)
    T1 = P1 + [r1*cos(gamma1), r1*sin(gamma1)];
    T2 = P1 + [r1*cos(gamma2), r1*sin(gamma2)];
     M = [T1;T2];
function [len] = ArcLength(P1,P2,r)
=========================================================================
    c = sqrt((P1(1)-P2(1))^2 + (P1(2)-P2(2))^2);
theta = acos(1-c.^2./(2.*r.^2));
  len = r.*theta;

Best Answer

The fhs2 that you create is a string, but you need to pass fzero a function handle. str2func(fhs2) to create the function handle.
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