minimal maxima function def to use mfuncall?



What is the minimum amount of preparation one
must do in defining a maxima function using :=
to be able to use it with mfuncall?
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(%i1) :lisp (mfuncall '$sin  '1.570796)
0.9999999999999466

(%i1) f(x) := x^2$

(%i2) :lisp (mfuncall 'f  '3)
((F SIMP) 3)

(%i2) 
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Ted Woollett