Determine if a function is continuous

In summary, continuity is a property of a function where there are no sudden jumps or breaks in the graph as the input values change. A function is continuous at a specific point if its limit exists and is equal to the value of the function at that point. Continuity is a local property, so a function can be continuous at one point but not at another. Polynomial, rational, exponential, and trigonometric functions are always continuous. The continuity of a function does not necessarily guarantee its differentiability, but a function must be continuous to be differentiable.
  • #1
kendalgenevieve
6
0
\(\displaystyle f(x)=\begin{cases}\dfrac{x^2-4}{x+2}, & x\ne-2 \\[3pt] 4, & x=-2 \\ \end{cases}\)

Determine if its continuous at x=-2
 
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  • #2
To ensure continuity, we require:

\(\displaystyle \lim_{x\to-2}\frac{x^2-4}{x+2}=4\)

Is this true?
 
  • #3
MarkFL said:
To ensure continuity, we require:

\(\displaystyle \lim_{x\to-2}\frac{x^2-4}{x+2}=4\)

Is this true?

I just got -4 so no it does not equal 4
 
  • #4
Hi kendalgenevieve! Welcome to MHB! ;)

kendalgenevieve said:
I just got -4 so no it does not equal 4

Good!
That means it's not continuous.
 

FAQ: Determine if a function is continuous

1. What is continuity?

Continuity is a property of a function where the output values of the function change gradually as the input values change. In other words, there are no sudden jumps or breaks in the graph of the function.

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

A function is continuous at a specific point if the limit of the function at that point exists and is equal to the value of the function at that point. In other words, as the input values approach the specific point, the output values also approach the same value.

3. Can a function be continuous at one point but not continuous at another?

Yes, a function can be continuous at one point but not continuous at another. This is because continuity is a local property, meaning it is determined at a specific point and does not necessarily apply to the entire function.

4. What types of functions are always continuous?

Polynomial functions, rational functions, exponential functions, and trigonometric functions are always continuous. This means that they are continuous at every point in their domain.

5. How does the continuity of a function affect its differentiability?

If a function is continuous at a point, it does not necessarily mean that it is differentiable at that point. However, if a function is differentiable at a point, it must also be continuous at that point.

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