what is the error ?

[Bob Thompson]

That is not a MATLAB specific error, and I don't see anything within the problem context to define what A and B are supposed to be. Unfortunately, the best advice I know to offer is to double check any other context you may be given for the problem that may call out what A and B are supposed to be. If no additional information is given, I recommend asking the teacher for further clarification.

[Rik]

You can find guidelines for posting homework on this forum here. If you have trouble with Matlab basics you may consider doing the Onramp tutorial (which is provided for free by Mathworks). If your main issue is with understanding the underlying concept, you may consider re-reading the material you teacher provided and ask them for further clarification.

[James Tursa]

Please post your code as regular text highlighted by the CODE button. We can't copy & run images.

[shamsa khalid]

syms t
f=@(t)t^2
g=@(t)5*t-1
h=@(t)2*t^3-t
r=[f(t) g(t) h(t)]
dr = diff(r,t);
T=dr/norm(dr);
dT=diff(T,t);
k=norm(dT)/norm(dr);
k=subs(k,1);
disp('Curvature at t=1;'),disp(k)
disp('Or,approximately;'),disp(double(k))