Continuity on piecewise function

In summary, the function f(x) is continuous at x=-1, x>2 and discontinuous at x=1, x=2. At x=1 and x=2, the discontinuities are classified as jump discontinuities. The function is right continuous at x=-1 and left continuous at x=1. It is also continuous on the intervals (1,2) and (2, infinity).
  • #1
Wables
5
0

Homework Statement


[10 Marks] At which points is the following function continuous and at which point is it discontinuous. Explain the types of discontinuity at each point where the function is discontinuous. Then at each point of the discontinuity, if possible, find a value for f(x) that makes it continuous or one sided continuous.

f(x) =
-2x if -1[itex]\leq[/itex]x<1
-2/(x-1) if 1<x<2
x-2 if x> 2

Homework Equations



Test continuity at point:
f(a) is defined
lim f(x) exists
x->a
lim f(x) = f(a)
x->a

Continuity at Endpoints
lim f(x) = f(a) = left continuous
x->a-
lim f(x) = f(a) = right continuous
x->a+

The Attempt at a Solution



Im thinking what I need to do, is:
Check for continuity at the points -1, 1, 2.
Then I would classify any discontinuities as either removable, jump, or infinite discontinuities.
But that last part, I am not sure what its asking?
What I have is this so far:

Discontinuous at x=1 and x=2.
At x=1: Jump discontinuity
At x=2: Jump discontinuity

Im not sure if I am supposed to do this or if its right, but I did it anyway:
At x=-1, the function is right continuous on the interval [-1, 1). The function is also continuous on (1, 2) and (2, infinity)
 
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  • #2
Basically correct but the discontinuity at x= 1 is NOT a "jump" discontinuity:
[tex]\lim_{x\to 1^+} f(x)= \lim_{x\to 1}\frac{-2}{x- 1}= -\infty[/tex]
 
  • #3
Oh really? Cool! Thanks! So by stating the intervals of continuity, I satisfied the last part of the problem? Cause I was not sure what it was asking..
 

1. What is a piecewise function?

A piecewise function is a mathematical function that is defined by different equations or rules for different intervals or pieces of the domain.

2. What is continuity?

In mathematics, continuity is a property of a function where the output of the function changes only slightly when the input changes slightly.

3. How can I determine if a piecewise function is continuous?

To determine if a piecewise function is continuous, you need to check if the function is defined for all points in its domain and if the limit of the function at each point exists and is equal to the value of the function at that point.

4. What is a removable discontinuity in a piecewise function?

A removable discontinuity in a piecewise function occurs when the function is not defined at a certain point in its domain, but can be defined by changing the value of the function at that point to make it continuous.

5. Can a piecewise function be continuous but not differentiable?

Yes, it is possible for a piecewise function to be continuous but not differentiable. This can occur when the function has sharp turns or corners at certain points in its domain.

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