# Extremum of the function online calculator

Maximum of minimum point of the function called *extremum*. Look at the picture of
some function:

From the plot, one can conclude that the points
(x_{1},
y_{1}),
(x_{3},
y_{3})
are maxima of the function. The points
(x_{2},
y_{2}),
(x_{4},
y_{4})
are minima of the function. Both, these points are called extrema of the function.

The tangent of the function is extrema points is parallel to the abscissa axis (geometric sense). Hence, the derivative of the function equals to zero at extrema points (requirement of the extrema). In addition, derivative may not exist in extrema points.

Sometimes, we need to find minimal (maximal) value of the function at some interval
[a,
b]. In this case, one need to find all the
*extrema points* which belongs to this intervals and also check the values of the function at the borders of the interval.

## Choose expression input type:

## Set options to find function's extremum:

Choose stationary point type:

Function's variable