Proving partial deviatives not continous

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SUMMARY

The discussion centers on proving the continuity of the partial derivative fx(x,y) of the function f(x,y) = y^2 + (x^3)sin(1/x) for x ≠ 0 and f(0,y) = y^2 for x = 0 at the point (0,0). The user initially calculated the partial derivative as fx = 3(x^2)sin(1/x) - xcos(1/x) and found that the limit as (x,y) approaches (0,0) equals 0, which matches the value of fx(0,0). However, the user questions their conclusion about continuity, suggesting that the lack of oscillation in the graph indicates continuity. The analysis reveals a misunderstanding of the definition of continuity in the context of partial derivatives.

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Homework Statement


f(x,y) = y^2 + (x^3)*sin(1/x) when x =/= 0
= y^2 when x = 0

i want to prove fx(x,y) is not continuous at (0,0)

Homework Equations





The Attempt at a Solution


i found when x=/=0 , fx = 3(x^2)sin(1/x) - xcos(1/x) -----eq(1)
and limit(x,y -> 0,0) eq(1) = 0 as sin and cos is bounded
and the actual fx(0,0) = limit(h->0) (f(h,0)-f(0,0))/h = lim(h->0) (h^2)*sin(1/h) = 0
it seem limfx(0,0) = fx(0,0)
so i cannot conclude that fx is not continuous at (0,0)
where did i go wrong?
 
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can someone offer help please?.
 
I think the partial derivative is actually continious. Graphing it shows it has no oscillation, which is a quantitative definition of continuity.
 

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