Help with this small exercise with input/output and ezplot

The exercise asks:

I wrote this matlab code

function y=sineseries(x,n)
x1=input('Insert the 1st value here -> ');
x2=input('Insert the 2nd value here -> ');
x3=input('Insert the 3rd value here -> ');
x4=input('Insert the 4th value here -> ');
x=[x1, x2, x3, x4];
n=input('Insert the integer index n-> ');

while n<0
    disp('Error: n must be positive');
    n=input('Insert n again -> ');
end
    
sol=0;

for k=1:n
s=(-1).^(k-1)*x.^(2*k-1)./factorial(2*k-1);
sol=sol+s;
end

format long
y=sol


end 

My questions are:

1) how do I modify the code in order to have an appropriate y?

2) how do I use the command ezplot as it is asked in the exercise?

Answer 1

[Bohdan Syrotiuk]

It's not a so easy excercise...