Euler's approximation for ODE

I want want to use MATLAB to implement Euler’s method with each step size h= 0.2,0.1,0.05 for 0≤t≤1 and plot the results in a single figure. I would like to also solve the ODE and plot the exact solution in the same in compare the two.

How do i fix this error:

Error: File: M1.m Line: 5 Column: 7

Invalid use of operator.

euler is a function i wrote.

f = @(t,y) t*y-y;
y0 = 0.5;
i = 0.2; 

for i >= 0.05  
    t = 0:i:25;
    [t,y1] = euler(f,t,y0);
    i=i/2 
    plot(t,y1)
end 

y2 = -1 ./ (t.^2/2 + 10);
plot(t,y2)

legend('Euler','Exact solution')
save(M1.fig)

[darova]

It's not Euler's method

[t,y1] = euler(f,t,y0);

Answer 1

[Lucademicus]

for i >= 0.05  

This is not the correct way to define a for-loop.

See the documentation for the correct syntax: https://mathworks.com/help/releases/R2018b/matlab/ref/for.html?searchHighlight=for&s_tid=doc_srchtitle

Also, with the error message MATLAB tries to point you in the right direction, by telling you 1) what is not working, 2) where it is not working. I would want to advise you to take a look at what line number (and column number) MATLAB mentions and then looking in the documentation regarding the code you're using on that line.