HP 48gII - Manual (Page 448)

Page 13-13
For example, to determine where the critical points of function 'X^3-4*X^2-
11*X+30' occur, we can use the following entries in ALG mode:
We find two critical points, one at x = 11/3 and one at x = -1. To evaluate
the second derivative at each point use:
The last screen shows that f”(11/3) = 14, thus, x = 11/3 is a relative
minimum. For x = -1, we have the following:
This result indicates that f”(-1) = -14, thus, x = -1 is a relative maximum.
Evaluate the function at those points to verify that indeed f(-1) > f(11/3).
Higher order derivatives
Higher order derivatives can be calculated by applying a derivative function
several times, e.g.,