FuncApplication

FuncApplication

FuncApplication[ f, a ] evaluates a function or mapping for an input value.

Usages

FuncApplication[ x->expr, a ] or f[ a ]

FuncApplication[ x->expr, a ] substitutes a for x in expr. If a script variable f is defined as a mapping, f[a] gives the same result as FuncApplication[f, a]. The result is not calculated; use Simplify for that.

Example in out
Substitute 4 in x^2+3x. FuncApplication[ x->x^2+3x, 4 ] 4^2+3*4
Calculate the result with Simplify. Simplify[ FuncApplication[ x->x^2+3x, 4 ] ] 28
A mapping stored in a script variable. f := t -> t^2
r := f[3]		 r = 3^2
A mapping and an input stored in script variables. f := t -> Sin[t]
x := Pi
r := f[x]		 r = Sin[Pi]
A mapping with two variables: give the values as a list. FuncApplication[ {x,y}->x+y, {1, 2} ] 1+2
A function name. FuncApplication[ Sqrt, 9 ] Sqrt[9]

FuncApplication[ list, i ]

If the first argument is a list, FuncApplication[ list, i ] returns the element at position i (starting at 1).

Example in out
The second element. FuncApplication[ {a, b, c}, 2 ] b
Note

FuncApplication does not currently support evaluating variables for intermediate parts in the Algebrakit CMS.

Details
  • Display: FuncApplication[ f, x ] is displayed as f(x)f\left(x\right), for example in a definition or an answer.
  • A constant as the first argument is returned unchanged: FuncApplication[ 5, 2 ] gives 5.
Invalid input Result
FuncApplication[ {a, b, c}, 5 ] Left unevaluated: the position is outside the list.
FuncApplication[ g, 2 ] (g not defined) Left unevaluated.

See also: Map, Apply, Substitute, Simplify