Discussing continuity of a function

In summary, the function f defined for all x belongs to [0,1] by f(x)=x if x is rational and f(x)=x^2 is x is irrational is a combination of two functions that are discontinuous at most points. However, it is continuous at x=0, as the limit of both functions approaches 0 at that point. It is not continuous at any other point in the interval due to the existence of both rational and irrational numbers, which leads to the existence of gaps in the function.
  • #1
kmeado07
40
0

Homework Statement



Discuss the continuity of the function f defined for all x belongs to [0,1] by f(x)=x if x is rational and f(x)=x^2 is x is irrational.

Homework Equations





The Attempt at a Solution



I have no idea how to begin this question...some help would be great thanks!
 
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  • #2
Maybe you should try checking some points. Is f continuous at 0? How about sqrt(2)?
 
  • #3
You will need to know
1) The definition of "continuous at a point".
2) The fact that there exist rational numbers in any interval, no matter how small.
3) The fact theat there exist irrational numbers in any interval, no matter how small.
The last two should help you find the limit, or determine if it does not exist, at any point.
 

FAQ: Discussing continuity of a function

What is continuity of a function?

Continuity of a function refers to the property of a mathematical function that describes the behavior of the function as its input values change. A function is continuous if it has no breaks or gaps in its graph and its output values change gradually as the input values change.

How is continuity of a function determined?

Continuity is determined by three conditions: the function must be defined at a point, the limit of the function as it approaches that point must exist, and the limit must be equal to the function's value at that point. If all three conditions are met, the function is considered continuous at that point.

What is the importance of continuity in mathematics?

Continuity is an important concept in mathematics because it allows us to analyze and understand the behavior of functions. Continuity helps us determine the existence of limits, solve differential equations, and understand the behavior of real-world phenomena.

Can a function be continuous at some points but not others?

Yes, a function can be continuous at some points and not others. This is known as a discontinuous function. A function can be discontinuous due to a break or gap in its graph, or because one of the three conditions for continuity is not met at a specific point.

How can we prove that a function is continuous?

We can prove that a function is continuous by showing that it meets all three conditions for continuity at a specific point. This can be done using the definition of continuity, along with theorems and properties of continuous functions. Additionally, we can use techniques such as the epsilon-delta proof or the intermediate value theorem to show that a function is continuous.

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