Is a graph Continuous and differentiable at a given point

  • Thread starter betsinda
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  • #1
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Homework Statement



F
f(x)={(2x-1)/Absolute value(2x-1) x cannot equal (1/2)
{ 0 x = (1/2)

a) is f continous at X = (1/2) explain
b) is f differentiable at x = (1/2) explain

Homework Equations



I have made the graph and x is a point at 1/2 but there is a jump. I have no idea how to start this.



The Attempt at a Solution

 

Answers and Replies

  • #2
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Drawing a graph is a good start. Can you describe what the graph looks like?
 
  • #3
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the line from the left approachs (1/2) at +1 and restarts at (1/2) at -1. There is a single point at (0,1/2)
 
  • #4
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sorry it continues to the right at -1
 
  • #5
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the line from the left approachs (1/2) at +1 and restarts at (1/2) at -1. There is a single point at (0,1/2)

No, none of this is right. The graph of this function is in three parts--two horizontal lines and a single point.

What is f(-1)? f(0)? f(1/2)? f(1)? f(2)? Plotting these points should give you an idea of what the graph of the function looks like.
 
  • #6
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okay, I have fixed the graph. I have a line going from (1/2, 1) (1,1)(2,1) ect and a line going from (1/2,-1)(0,-1)(1,-1) ect, and a point at (1/2,0).

How do i determine if this is continous at 1/2?
 
  • #7
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One quibble. The line doesn't contain the point (1/2, -1). Does the graph look continuous at x = 1/2?
 
  • #8
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I would say that the graph is not continuous at x=1/2 as that point does not connect to any other point on the graph.
 
  • #10
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would it then be correct to say that x=1/2 is not differentiable as it is not continuous at that point?
 
  • #11
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based on the fact that well every function is not differentiable, very function that is differentiable is continous. Or am I misunderstanding the concept?
 
  • #12
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would it then be correct to say that x=1/2 is not differentiable as it is not continuous at that point?
No. It doesn't make any sense to talk about a point or an x value being differentiable. You can say, though, that a function is continuous or differentiable at a point or at some x value.
 
  • #13
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based on the fact that well every function is not differentiable, very function that is differentiable is continous. Or am I misunderstanding the concept?
That is correct, so you are not misunderstanding the concept. I have made a couple of edits to what you wrote:
While not every function is differentiable, every function that is differentiable is continous.
 
  • #14
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B) is f differentiable at x = (1/2) explain

So I could say that function is not differentiable at x=1/2 as the function is not not continuous?

Sorry for being a little slow i'm just trying to wrap my head around the concept. Thanks
 

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