How can I get maximum and minimum value with sym variables

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.

Answer 1

[madhan ravi]

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.