Finding error in Trapozidal rule

[hrr379]

I understand that in order to calculate the error E_T = _a∫^b f(x) dx = T_n

|E_T| ≤ K(b-a)³ /(12n²)

How do I find K?

Is K is the n^th prime of a function?

 

[tkhunny]

Well, sort of, but a little less clear than that. If you find the derivative, where will you evaluate it?

1) You must find the right derivative.
2) You must find the maximum value of that derivative.

The first question is which derivative is it? It's not the nth derivative unless you pick the right value for 'n'.