[list=1][*]In the input bar type [b]f(x)=x^2[/b] and press enter.[br][br][/*][*]Add a [b]New Point[/b], A,on the curve[br][br][/*][*]In the input bar set [b]a=x(A)[/b][br][br][/*][*]Add a [b]Slider[/b]: Name: h,  Min: 0, Max 1, Increment 0.01.[br][br][/*][*]In the input bar add the point [b](a+h, f(a+h))[/b][br][br][/*][*]Add the [b]Line[/b] through A and B[br][br][/*][*]In the input bar set [b]H=f(a+h)-f(a)[/b][br][br][/*][*]In the input bar set [b]q=H/h[/b][br][br][/*][*]Create a [b]Text box[br][/b]- switch LaTeX formula on[br]- in the Advanced tab select the fraction a/b[br]- replace a and b with H and h from the GeoGebra objects menu [br]- type [b]=[/b] [br]- select q from the GeoGebra objects menu[br][/*][/list]