I will not re-post your entire code, only the lines you need to change:
j=(1-k*u)./sqrt(k-k*k*power(u,2)); % <— USE ELEMENT-WISE DIVISION OPERATOR HERE
l=(1-u)./sqrt(1/k-power(u,2)); % <— USE ELEMENT-WISE DIVISION OPERATOR HERE
e=(1+k*u);
f=sqrt(k-k*k*power(u,2));
g=e./f; % <— USE ELEMENT-WISE DIVISION OPERATOR HERE
m=(1+k*u)./sqrt(k-k*k*power(u,2)); % <— USE ELEMENT-WISE DIVISION OPERATOR HERE
n=(1+1*u)./sqrt(1/k-power(u,2)); % <— USE ELEMENT-WISE DIVISION OPERATOR HERE
I do not know what result you expect, but this will plot a curve of the sort I believe you want.
