Hi, folks, I'm now a proud owner of a full Mathematica licence and trying to understand the language. Actually I'll understand the following, small program:

Euler[a0_, b0_, steps0_, x0_, v0_] :=

Module[{a = a0, b = b0, steps = steps0, xinit = x0, vinit = v0},

dt = (b - a)/steps;

k = 5.0;

m = 2.0;

c = 0.5;

f[{t_, x_, v_}] := v;

g[{t_, x_, v_}] := -x (k/m) - c v;

euler[{t_, x_, v_}] := {t + dt, x + dt f[{t, x, v}],

v + dt g[{t, x, v}]};

NestList[euler, {a, xinit, vinit}, steps]]

result = Euler[0, 20, 100000, 1, 1];

ListPlot[{result[[All, 2]], result[[All, 3]]}, PlotRange -> All]

I've no idea, why obviously the function values of curve 1 are stored in

result[[All, 2]] and the values of curve 2 in result[[All, 3]]. Every hints, where I can find further information ( books?) are highly appreciated! Thank you very much!

Peter