Question

what is slider and functions

Answer 1

The basic slider is horizontal and has a single handle that can be moved with the mouse or by using the arrow keys.

Answer 2

The first argument, functions , is either a list of functions or a single function that entails the commands for the sliders. If there are three sliders and slider 2 is moved with the mouse the function stored in functions(or in case of one function for all sliders the function sl. functions is called.

Hope this helps!