f(x) = (x - 2)^2
m = (f(x + h) - f(x)) / h
m = ((x + h - 2)^2 - (x - 2)^2) / h
m = ((x - 2 + h)^2 - (x - 2)^2) / h
m = ((x - 2)^2 + 2*(x - 2)*h + h^2 - (x - 2)^2) / h
m = (2*(x - 2)*h + h^2) / h
m = (2*(x - 2) + h)
wenn jetzt x = 3 und h --> 0 gilt
m = (2*(3 - 2) + 0) = 2