Proving Symmetric Continuity of a Function at X0

In summary, symmetric continuity at a point X0 is when the limit of the function as h approaches 0 from both sides is equal to 0. If a function is continuous at X0, then it is also symmetrically continuous at that point. However, the converse is not always true, as shown by the example of the function f(x) = x if x is nonzero and f(0) = 1, which is symmetrically continuous at 0 but not continuous.
  • #1
mrs.malfoy
3
0
A function f is said to be symmetrically continuous at X0 if

lim [f(X0 + h) - f(X0 - h)]= 0
h-> 0



Show that if f is continuous at X0, it is symmetrically continuous there but not conversely.
 
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  • #2
This sounds like homework so I'm not going to go into too much detail, but note that if f is continuous at x then: [tex]lim_{h\rightarrow0}f(x+h)=lim_{h\rightarrow0}f(x-h)=f(x).[/tex]

There isn't much more to do.
 
  • #3
For the converse, take
f(x) =x if x is nonzero ,
f(0) =1.
f is symmetrically continuous at 0, but not continuous.
 

1. What is symmetric continuity?

Symmetric continuity is a property of a mathematical function that describes its behavior at a specific point, called x0. A function is symmetrically continuous at x0 if it has the same limit from the left and the right at x0, and the value of the function at x0 is equal to its limit.

2. How is symmetric continuity different from regular continuity?

Regular continuity requires that the limit of a function exists and is equal to the value of the function at a specific point. Symmetric continuity, on the other hand, also requires that the limit from the left and the right at that point are equal.

3. How do you prove symmetric continuity of a function at x0?

To prove symmetric continuity of a function at x0, you need to show that the limit of the function from the left and the right at x0 is equal, and that the value of the function at x0 is also equal to this limit. This can be done using the epsilon-delta definition of limits, where you choose an arbitrary epsilon and find a corresponding delta that satisfies the definition.

4. What are some common mistakes when proving symmetric continuity?

One common mistake is forgetting to check that the limit from the left and the right at x0 are equal. Another mistake is assuming that regular continuity automatically implies symmetric continuity. Additionally, using the wrong epsilon-delta definition or not following the steps correctly can also lead to errors.

5. Why is proving symmetric continuity important?

Proving symmetric continuity is important because it ensures that a function is well-behaved at a specific point. This means that the function is continuous from both sides, and there are no sudden jumps or discontinuities at that point. It also allows for easier analysis and calculations of the function's behavior at that point.

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