f(x)=

f(x) = x^(3)
Eingabefeld1 = Textfield(f)
h = 0.883995001 (slider from 1.0E-9 to 1.2, step 1.5E-5)
g(x) = (f(x + h) - f(x)) / h
Text1 = LaTeX(g, true, true)
L_1 = Sequence((f(x + n) - f(x)) / n, n, 1.0E-9, h, 0.1)