MATLAB: Why am i getting that error

Question

please help

i am writting a code for the trapz rule for numerical integration and i keep getting that error

Array indices must be positive

integers or logical values.

Error in sym/subsref (line 900)

R_tilde =

builtin('subsref',L_tilde,Idx);

Error in tarpz (line 12)

y(i) = F(x(i));

and that is my code

clc

clear all

syms x

A = input('the upper limit = ');

B = input (' the lower limit = ');

N = input (' number of intervals = ');

H = (B-A)/N;

F = input ('function = ');

sum = 0;

for i = 1:1:N-1

x(i) = A + i * H;

y(i) = F(x(i));

sum=sum+y(i);

end

Area = H/2*(F(A)+F(B)+2*sum);

fprintf (' integration value is %.4f\n',Area);

Answer 1

The Symbolic Math Toolbox does knt know that ‘F’ is a function.

Try this instead:

F(x) = input ('function = ');

That worked when I tried it.