Problem of graph with ListPlot

2018-02-23 16:26:46

I don't understand why, but, with this code, I can't get a graph. Nothing is happening in output. And I have no errors.. Here is the code:

ListPlot[RecurrenceTable[{a[n + 1] == (a[n] + b[n])/2,

b[n + 1] == (2 / (1 / a[n] + 1/b[n])), a[0] == 4, b[0] == 3}, {a,

b}, {n, 0, 30}],

PlotRange -> {0, 100},

ImageSize -> 400,

AxesLabel -> {"n", "anbn"},

PlotLabel -> "Premiers Termes :-) "

]

Do you know what is the problem?

Thanks for your time!!!