Extremum Command

Extremum[ <Polynomial> ]

Yields all local extrema of the polynomial function as points on the function graph.

Example:
Extremum[x³ + 3x² - 2x + 1] creates local extrema points - (0.29, 0.696) and (-2.3, 9.3) - and shows them in the Graphics View.

Extremum[ <Function f>, <left-x>, <right-x> ]

Calculates (numerically) the extremum of f in the open interval ( <left-x>, <right-x> )

Note: Function f should be continuous in [ <left-x>, <right-x> ], otherwise false extremums near discontinuity might be calculated.

Example:
Extremum[(x⁴ - 3x³ - 4x² + 4) / 2, x(X_i), x(X_f)] creates each local extrema point in the given interval and shows it in the Graphics View.