- #1
e(ho0n3
- 1,357
- 0
Homework Statement
Let f be a function with the property that every point of discontinuity is a removable discontinuity. This means that [tex]\lim_{y\to x} f(y)[/tex] exists for all x, but f may be discontinuous at some (even infinitely many) numbers x. Define [tex]g(x) = \lim_{y\to x} f(y)[/tex]. Prove that g is continuous.
The attempt at a solution
So I have to prove that for all a,
[tex]\lim_{x \to a} g(x) = \lim_{x \to a} \lim_{y\to x} f(y) = g(a) = \lim_{y\to a} f(y) [/tex]
In other words, for every e > 0, there is a d > 0 such that
[tex]\left| \lim_{y\to x} f(y) - \lim_{y\to a} f(y) \right| < e[/tex]
for all x satisfying |x - a| < d. I have no clue how to find d. Any tips.
Let f be a function with the property that every point of discontinuity is a removable discontinuity. This means that [tex]\lim_{y\to x} f(y)[/tex] exists for all x, but f may be discontinuous at some (even infinitely many) numbers x. Define [tex]g(x) = \lim_{y\to x} f(y)[/tex]. Prove that g is continuous.
The attempt at a solution
So I have to prove that for all a,
[tex]\lim_{x \to a} g(x) = \lim_{x \to a} \lim_{y\to x} f(y) = g(a) = \lim_{y\to a} f(y) [/tex]
In other words, for every e > 0, there is a d > 0 such that
[tex]\left| \lim_{y\to x} f(y) - \lim_{y\to a} f(y) \right| < e[/tex]
for all x satisfying |x - a| < d. I have no clue how to find d. Any tips.