MATLAB: I’m trying to make a Simpsons Rule Function Myself

algorithmfunctionshomeworksimpsons rule

I've had a few attempts at this question and have developed my answer further each time. If people wouldn't mind giving feedback or correcting my code that'd be great.
This is the question:
Simpsons Rule Question Only.JPG
and the code I have written to answer this is, there is more to th question but this is just my code for the first bit:
function [y] =MPR_Asgn4_Q4a_26024405(f,a,b,n)
h=(b-a)/n;
x=zeros(1,n+1);
x(1)=a;
x(n+1)=b;
s1=0;
s2=0;
s3=0;
for k = 2:n
    x(k)=a+h*(1i-1);
end
for k=1:n/2
    s1= s1 + f(x(2*1i-1));
end
for k=1:n/2
    s2=s2+f(x(2*1i));  
end
for k= 1:n/2
    s3 = s3 +f(x(2*1i+1));
end
    
y = (h/3)*(s1+(4*s2)+s3);
disp(y);
end

Best Answer

Hi Jack,
I fixed your code as much as I can. You can use the code below: 
function [y] =MPR_Asgn4_Q4a_26024405(f,a,b,n)
    x = linspace(a,b,n);
    x(1)=a;
    x(n+1)=b;
    h=(b-a)/n;
    s1=0;
    s2=0;
    s3=0;
    %First if statements is to check if f is an anonymous function  
    %or an array.
    
    if length(f) >  1%array state
        %if it is a array your sub intervals will be the length of array
        %So you have to update it.
        n = length(f)-1;
        h=(b-a)/n;
        for k=3:2:length(f)-2
            s1= s1 + 2*f(k);
        end
        for k=2:2:length(f)
              s2=s2+f(k);
        end
        s3 = f(length(f));
        y = (h/3)*(f(1)+(2*s1+(4*s2)+s3));
    else%anonymous function state
        
        for k=3:2:length(f)-2
            s1= s1 + 2*f(x(k));
        end
        for k=3:2:length(f)
              s2=s2+f(x(k));
        end
        s3 = f(length(f));
        y = (h/3)*(f(x(1))+(2*s1+(4*s2)+s3));
    end
    disp(y);
end
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