Student[VectorCalculus][PositionVector] - creates a position vector with specified components and a coordinate system
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Calling Sequence
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PositionVector(comps)
PositionVector(comps, c)
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Parameters
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comps
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list(algebraic); the components of the Position Vector
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c
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name or name[name, name, ...]; specify the coordinate system possibly indexed by the coordinate names
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Description
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For details on the differences between the four principal Vector data structures, namely, position Vectors, rooted Vectors, free Vectors, and vector fields, see VectorCalculus,Details.
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The call PositionVector(comps, c) returns a position Vector in a cartesian enveloping space with components interpreted using the corresponding transformations from c coordinates to cartesian coordinates.
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If no coordinate system argument is present, the components of the position Vector are interpreted in the current coordinate system (see SetCoordinates).
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The position Vector is a cartesian Vector rooted at the origin. This has no mathematical meaning in non-cartesian coordinates, so the c parameter only changes the way the components are interpreted. Note that the Student[VectorCalculus] package only supports the cartesian, polar, spherical and cylindrical coordinate systems.
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If comps has indeterminates representing parameters, the position Vector serves to represent a curve or a surface.
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To differentiate a curve or a surface specified via a position Vector, use diff.
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To evaluate a vector field along a curve or a surface given by a position Vector, use evalVF.
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The position Vector is displayed in column notation in the same manner as rooted Vectors are, as a position Vector can be interpreted as a Vector that is (always) rooted at the cartesian origin.
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A position Vector cannot be mapped to a basis different than cartesian coordinates. In order to see how the same position Vector would be described in other coordinate systems, use GetPVDescription.
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Binary operations between position Vectors and vector fields, free Vectors or rooted Vectors are not defined; however, a position Vector can be converted to a free Vector in cartesian coordinates via ConvertVector.
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Examples
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Position Vectors
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Curves
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Surfaces
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