

Factorial[3] ->
3*Factorial[2] ->
3*2*Factorial[1] ->
3*2*1 ->
6*1 ->
6
x2 + 3y2 = Plus[Power[x, 2], Times[3, Power[y, 2]]]
{1, 2, 3} = List[1, 2, 3]
First[List[a_, __]] := a
First[{1, 2, 3}] -> 1{# + 1}& /@ {1, 2, c, 4} =
Map[{# + 1}&, {1, 2, c, 4}] ->
{2, 3, c, 5}



trainingset = {1 -> "A", 2 -> "A", 3.5 -> "B", 4 -> "B"}
c = Classify[trainingset]
c[2.6]
c[2.6, "Probabilities"]



