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Question: Why isn't the result in a consistent form?

Question:Why isn't the result in a consistent form?

DJJerome1976 535
vector unapply vectorcalculus
March 26 2013
1

Can anyone explain the inconsistency in the following?

 

with(VectorCalculus):

f := proc (x, y) options operator, arrow; x^2+y^3 end proc:

Gradient(f(x, y), [x, y])

2*x*`#mover(mi("e"),mo("_"))`[x]+3*y^2*`#mover(mi("e"),mo("_"))`[y]

 (1)

gradf := unapply(Gradient(f(x, y), [x, y]), [x, y]):

gradf(x, y)

2*x*`#mover(mi("e"),mo("_"))`[x]+3*y^2*`#mover(mi("e"),mo("_"))`[y]

 (2)

gradf(1, 1)

Vector(2, {(1) = 2, (2) = 3})

 (3)

``

Why is result from gradf(x,y) given as a linear combination of the appropriate unit vectors, but gradf(1,1) given as a column vector? How can consistency be acheived?

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