MATLAB: How to get maximum and minimum value with sym variables

MATLABmaxsymssyms max value

clear; clc; close all;
syms seta
gamma = 1;
Rx_ = 1;
Ry_ = Rx_*gamma;
% 등가 정적 적용
gamma = 1;
Rx1= ( cos(seta)-0.3*sin(seta) )*Rx_ ;
Rx2= ( cos(seta)+0.3*sin(seta) )*Rx_;
Rx3= ( 0.3*cos(seta)-sin(seta) )*Rx_;
Rx4= ( -0.3*cos(seta)-sin(seta) )*Rx_;
Ry1= (0.3*cos(seta) + sin(seta) )*Ry_;
Ry2= (-0.3*cos(seta) + sin(seta) )*Ry_;
Ry3= (cos(seta) + 0.3*sin(seta) )*Ry_;
Ry4= (cos(seta) - 0.3*sin(seta) )*Ry_;
N=4;
for ii=1:N
   temp=['RR',num2str(ii),'=Rx',num2str(ii),'+Ry',num2str(ii),';'];
   eval(temp);
 end
here is my code, then I get 
RR1 =
 (13*cos(seta))/10 + (7*sin(seta))/10
 
RR2 =
 (7*cos(seta))/10 + (13*sin(seta))/10
etc.
and now I want to get the max and min value and seta value at that point. but I don't know how I get it. the max(), min() didn't work for syms funtion.

Best Answer

Use matlabFunction() and fminbnd() to find the minimum value of that function and to find the maximum extreme use negative sign for the function and feed it to fminbnd().
 doc matlabFunction
 doc fminbnd
And as always eval() here is completely not necessary and should be avoided.
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