Is the Function x->|x| Differentiable at 0?

In summary, differentiability is a mathematical property of a function that is both continuous and has a defined derivative at a given point. This can be determined using the limit definition of a derivative. Differentiability and continuity are related but different concepts, with differentiability requiring a defined slope at a point and continuity requiring a defined value. A function cannot be differentiable but not continuous. Differentiability has many real-life applications, including modeling and analyzing rates of change and solving optimization problems.
  • #1
losin
12
0
I want to show x->abs(x) is not differentiable at 0

Some techniques in analysis are required... how should i do?
 
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  • #2
Calculate left and right limit of the difference quotient. If the function were differentiable, these would coincide, but they don't.
 
  • #3
More basically ... use the definition of derivative.
 
  • #4
The definition is the limit of the difference quotient.
 

FAQ: Is the Function x->|x| Differentiable at 0?

1. What is the definition of differentiability?

The definition of differentiability in mathematics is the property of a function being continuous and having a defined derivative at a given point.

2. How do you determine if a function is differentiable at a point?

To determine if a function is differentiable at a point, you can use the limit definition of a derivative. If the limit exists and is finite, then the function is differentiable at that point.

3. What is the difference between differentiability and continuity?

Differentiability and continuity are related concepts, but they are not the same. A function that is continuous at a point may or may not be differentiable at that point. Continuity requires the function to have a defined value at that point, while differentiability requires the function to have a defined slope at that point.

4. Can a function be differentiable but not continuous?

No, a function cannot be differentiable but not continuous. Differentiability implies continuity, so if a function is differentiable at a point, it is also continuous at that point.

5. What are the applications of differentiability in real life?

Differentiability is a fundamental concept in calculus and is used in many areas of science and engineering. It is used to model and analyze rates of change, such as in physics, economics, and biology. It is also used in optimization problems, such as finding the maximum or minimum value of a function.

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