Index exceeds the number of array elements. Index must not exceed 2.

Hi. I have an error : Index exceeds the number of array elements. Index must not exceed 2. for line 16. Why ? and How can i fix this problem ?

clc; clear all;
t=[0 1];
h=0.01;
n=(t(2)-t(1))/h;
alpha=0.5;

%initials%
y_m(1)=2;
y_m(2)=exp(20.*h)+cos(h);
f_m(1)=20.*(y_m(1)-cos(t(1)))-sin(t(1));
f_m(2)=20.*(y_m(2)-cos(t(2)))-sin(t(2));


%Midpoint Two step method%
for i=3:n
    y_m(i)=y_m(i-2)+2.*h.*f_m(i-1);
    f_m(i)=20.*(y_m(i)-cos(t(i)))-sin(t(i));
end

[Jan]

Instead of writing "line 16" post a copy of the complete error message. Then the readers do not have to count and most of all: the 16th line is running without a problem, but the 17th fails...

Answer 1

[Jan]

for i=3:n
    y_m(i)=y_m(i-2)+2.*h.*f_m(i-1);           % <-- This is line 16
    f_m(i)=20.*(y_m(i)-cos(t(i)))-sin(t(i));  % <-- This line is failing
end

t(3) is not defined.

Answer 2

[Voss]

This error happens because t has only two elements, so there is no element t(3).

How to fix it depends on what the code should be doing.

[Hazel Can]

Thank you for your answer. I fixed this error.