f2[x_, y_] := x^2 + y^3;
g[t_] := {t^2, 3*t+1}
$g$ returns a list, but $f_2$ is a two variable function.
So, we cannot compose these functions:
f2[g[1]]
f1[v_] := v[[1]]^2 + v[[2]]^3
g[t_] := {t^2, 3*t+1}
We can compose these functions like the following:
f1[g[1]]
But I don't want to use a vector variable function like $f_1$.
Any good idea?
Does this work for you?
ClearAll[f2, g]
f2[{x_, y_}] := f2[x, y]
f2[x_, y_] := x^2 + y^3;
g[t_] := {t^2, 3*t + 1}
f2[g[1]]
65
It looks like you've already got several good answers, but I thought I would mention Apply.
f2[x_, y_] := x^2 + y^3
g[t_] := {t^2, 3 t + 1}
f2@@g[1]
65
The head of the result of evaluating g[1] is List, and Apply replaces this with f2. Essentially, List[1, 4] --> f2[1, 4].
And along the lines of @MassDefect,
f = {#1^2 + #2^3} &
g = {#1^2, 3 #1 + 1} &
f @@ g[1]
Pure functions can be a solution too. Result is {65} as expected.
f1[{x_,y_}]:=x^2+y^3be what you want? – John Doty Feb 29 '20 at 02:15