Question 67002
F(x + h) - F(x - h)/2h
2(x + h) - 2(x - h)/2h
2x + 2h - (x - h)/h
(2xh + 2h^2)/h + (h - x)/h
(2h^2 + 2xh + h - x)/h
2h + 2x + 1 - x/h