Is F = ∇f if DF1/Dy = DF2/Dx for F(x,y) = (ycos(x), xsin(y))?

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SUMMARY

The discussion centers on the function F(x,y) = (ycos(x), xsin(y)) and the condition that if F = ∇f for some function f: R² → R, then the equality DF1/Dy = DF2/Dx must hold. Participants conclude that F does not represent the gradient of a function f due to the lack of continuous partial derivatives, which violates Clairaut's theorem regarding the symmetry of second partial derivatives. The analysis emphasizes the necessity of continuous partial derivatives for the gradient condition to be satisfied.

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  • Understanding of vector calculus and gradient fields
  • Familiarity with partial derivatives and their properties
  • Knowledge of Clairaut's theorem on the symmetry of second derivatives
  • Basic concepts of multivariable functions
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Homework Statement


consider a function F : R^2 [tex]\rightarrow[/tex]R^2 given as F(x,y)=(F1(x,y),F2(x,y)).Show that if F=[tex]\nabla[/tex]f for some function f : R^2[tex]\rightarrow[/tex]R,then
(for partial derivative )
DF1/Dy=DF2/Dx
show that F(x,y)=(ycos(X),xsin(y))is not the gradient of a function


Homework Equations





The Attempt at a Solution


i don't know how to set about this question
any clue ?
 
Last edited:
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