Error : Index exceeds the number of array elements

I am getting this error at line 25 for phi(i). How can i resolve this

t = 0.12;

Vinf = 1;

ang = 0;

n = 50;

c = 1;

j1 = 1:1:(n/2)+1;

dx = 2*c/n;

p0= 0.2969;

p1=-0.1260;

p2=-0.3516;

p3= 0.2843;

p4=-0.1015;

X = (j1-1)*dx;

Y1 = X .* (t/0.2) .* (p0*sqrt(X) + p1*X + p2*X.^2 + p3*X.^3 + p4*X.^4);

for i=1:n

phi(i)=-ang+atan2((Y1(i+1)-Y1(i)),(X(i+1)-X(i)));

beta(i)=phi(i)+pi/2;

mpX1(i)=(X(i+1)+X(i))/2;

mpY1(i)=(Y1(i+1)+Y1(i))/2;

S(i)=sqrt((Y1(i+1)-Y1(i))^2+(X(i+1)-X(i))^2);

end

Answer 1

[David Fletcher]

Y1 and X will be the same dimension as j1 - (n/2)+1 (26). Once your for loop counter hits 26 you will get an error since you are trying to index elements that do not exist. The highest value of i that your for loop can run to is n/2