(a) Experiment with (14) for integer n. Using graphs, find out from which x = x_n on the curves of (11) and (14) practically coincide. How does x_n change with n?

(b) What happens in (b) if n = ±1/2? (Our usual notation in this case would be v.)

(c) How does the error of (14) behave as a function of x for fixed n? [Error = exact value minus approximation (14).]

(d) Show from the graphs that J₀(x) has extrema where J₁(x) = 0. Which formula proves this? Find further relations between zeros and extrema.