Vector field and differential form confusion

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Vector fields and differential forms are duals in mathematics, with differential forms evaluated at vector fields to yield numerical results. The discussion clarifies that the expression ∂/∂u is not a vector field. It also corrects a misrepresentation of the expression involving partial derivatives, emphasizing that it should relate to how x and y are functions of u and v. Understanding these distinctions is crucial for proper application in mathematical contexts. The conversation highlights the importance of accurate notation and definitions in vector calculus.
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Homework Statement
We have xy-plane, which is has a mapping (x,y). Another map is (u,v) and the transformation of coordinates are u=4x+3y and v=x+y.

1. Write vector field \frac{\partial}{\partial u} in the map (x,y)

2. Write the 1-form du in the map (x,y)
Relevant Equations
u=4x+3y and v=x+y.
Here is a picture of the solution I made :

1697563788231.png
So my question is: Are these right and how do they differ from each other?
 
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In a formal Mathematical sense, they're duals to each other. Differential forms are evaluated at Vector Fields to produce numbers.
 
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## \text { The first thing: } ##
## \frac { \partial } { \partial u } \text { is not a vector field. } ##

## \text { The second thing: } ##
## \text { The expression } \frac { \partial } { \partial u } = \frac { \partial u } { \partial x } \frac { \partial } { \partial x } + \frac { \partial u } { \partial y } \frac { \partial } { \partial y } \text { is not a correct expression. } ##
## \text { It should be } \frac { \partial } { \partial u } = \frac { \partial x } { \partial u } \frac { \partial } { \partial x } + \frac { \partial y } { \partial u } \frac { \partial } { \partial y } \text { where } x \text { and } y \text { are functions of } u \text { and } v \text { . } ##
 
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Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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