Trapezoid Rule (Simple)

disp("------------------------Trapezoid Rule------------------------")

% str = input('Give an equation in x: ','s')  ;
% a = input('Enter lowerbound value:');
% a
% b = input('Enter upperbound value:');
% b

str = "x*x*x+1"
a=1;
b=2;
a
b


h = (b-a);
h

% f = inline(str,'x') ;
f = str2func(['@(x) ',str]);

fa = feval(f,a) ;
fb = feval(f,b) ;
I = (h/2)*(fa+fb);
% disp("Value of y");
% y
% disp(['"' str '", for x = ' num2str(a) ', equals ' num2str(I)]) ;

disp(['Ans: ', num2str(I)])