Sorry about this dumb question in advance. Suppose I evaluate this :
test[x_, y_] := Laplacian[x^2 + y^2, {x, y}]
test[x, y] /. {x -> 1, y -> 1} (*4*)
Now if I try to do :
Sumovertest[x_, y_] := Sum[test[x + x^2 k, y + y^2 k ], {k, 0, 1}]
Sumovertest[x, y] /. {x -> 1, y -> 1} (4 + Laplacian[8,{2, 2}])
It treats the second variable as a numerical argument. I have tried Holding the form but it does not work. I know this must be super simple.
:=:test[x_, y_] = Laplacian[x^2 + y^2, {x, y}]– xzczd Aug 10 '23 at 00:30