# Syntax f[x_][y_]

Need to understand the principle of the distinction between f[x_,y_] and f[x_][y_]

It seems also that

z[x_, y_][a_, b_, c_][α_, β_] :=  a (x + y)^b + c/(α-β)


is interpreted by Mathematica since

Plot3D[z[x, y][2, 5, 3][2, 4], {x, 0, 1}, {y, 0, 1}]


gives a nice plot. It could be useful to distinguish between variables and two types of parameters. But, in that case, how to use association like

data1 = Association[Thread[{"a", "b", "c"} -> {.5, 1, 1}]]
data2 = Association[Thread[{"α", "β"} -> {.2, 3}]]


--- how to use Apply --- @@ ---

NB David Park shows to me that how to do in the simple following case

b[x_][y_] := x^y
(b @@ Values[da])[y]


If the association is on the first bracket-couple I can reproduce the example, but I do not know how to do it for a second bracket association.

• Look here. – march May 3 '16 at 17:35

(z[x, y]@@(Values[data1]))@@(Values[data2])

Plot3D[(z[x, y]@@(Values[data1]))@@(Values[data2]), {x, 0, 1}, {y, 0, 1}]