Why is my MATLAB plot wrong?

Hi! I just started my Matlab course and i have run into a little problem which i hope you can help me with. I am suppose to write a function which integrates a function e^(-t^2) from 0 to some x which is a variable in the function. I did that like this:

 function y = simpson_method(x)

 y1 = exp(-0.^2);
 y2 = exp(-(x).^2);

 c = 0;
 d = 0;
 incr = 0.1;

 for i = 1 : (x - 0)/incr - 0.5

    y = exp(-(0 + i*incr).^2);

    if i/2 == floor(i/2)

        d = d + y;
        continue
    else
        c = c + y;
        continue
    end
end

 y = incr/3 * (y1 + 4*c + 2*d + y2);

The function integrates correctly and gives me a desired output for every x. But the problem is when i try to plot it:

 x = 0:0.1:15;
 y = simpson_method(x);
 plot(x,y)

It gives me the wrong graph which i find weird because all the outputs are correct. I get this which is nonsense. Whats happening?

%

[Adam]

What is the right graph?

And what are the values of y that you get out?

[Edward Lisa]

This is the right plot and my function outputs y as very close to 0 when x=0 and reaches 0.884.. when x goes larger which is exactly the plot of the function when integrated on https://www.integral-calculator.com/ with input e^(-x^2) from 0 to your chosen upper limit.

[Stephen23]

@Edward Lisa: can you please confirm the ambiguous syntax:

1. e^((-t)^2)
2. e^(-(t^2))

[Edward Lisa]

Its e^(-(t^2))

[Adam]

If your y values are correct I can see no reason at all why plot would not give the correct answer so your y values cannot be correct if you are literally just calling plot.

Answer 1

[KALYAN ACHARJYA]

Shown Graph the x ranges are different