Topic: tangent in nbd of critical points

"Abnormal program termination " if say, we try and find the tangent of a non differentiable function at a point near (within about 0.2 units) the critical point .
eg:
Tangent of x^2/3 at 0.1
Sometimes it says that there is an "External exception EEFACE", instead of terminating.
Could anyone please explain what is going on?

Re: tangent in nbd of critical points

I am not able to reproduce the problem exactly as described. But if I try to insert a tangent to the function f(x)=x^(2/3) at x=0 I get the external exception. It is probably the same error you see. Fortunately it has been fixed in the beta version of Graph 4.4, which you can find at http://www.padowan.dk/graph/Beta.php