gives error index exceeds the number of array elements (33).

E=input('Enter E: ');
t=0:.01:2*pi;
G=64000;
while(E==0 || E== 1 || E == -1)
if E==0
r=G*t/2;
elseif E==-1
r=G.*(cosh(t)-1);
elseif E==1
r=G.*(1-cos(t));
end
plot(t,r)
E=input('Enter E: ');
end

[Mario Malic]

I don't get that error running this.

Though, you have E in the while loop, but it's not defined before it.

[Walter Roberson]

What sequence of input values are you using for E ?

Check your workspace in case you accidentally have a variable named plot

[Walter Roberson]

It appears that you were editing your quesiton at the same time I was posting my comment, so you might not have seen my comment.