Question: How to compute divergence and curl of 2D function

Please how do I compute the div n,  (n.curl n), (n.curl n)^2 and (n x curl n) and  (n x curl n)^2 given the information below: 

restart; restart; with(VectorCalculus); with(LinearAlgebra);


n = (cos(theta(x,y), sin(theta(x,y), 0).

I tried 

divn := Divergence(proc (x, y, z) options operator, arrow; `<,>`(n) end proc);

but received: Error, (in VectorCalculus:-Divergence) the procedure must evaluate to a Vector

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