Continuity

Description: This quiz is designed to assess your understanding of the concept of continuity in real analysis. It covers various aspects of continuity, including limits, epsilon-delta definition, and types of discontinuities.
Number of Questions: 16
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Tags: real analysis continuity limits epsilon-delta definition types of discontinuities
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Which of the following statements is true about the continuity of a function at a point?

  1. A function is continuous at a point if its limit at that point exists.

  2. A function is continuous at a point if its left-hand limit and right-hand limit at that point are equal.

  3. A function is continuous at a point if its derivative exists at that point.

  4. A function is continuous at a point if its graph has no breaks or jumps at that point.


Correct Option:
Explanation:

The epsilon-delta definition of continuity states that a function f(x) is continuous at a point c if for every epsilon > 0, there exists a delta > 0 such that if 0 < |x - c| < delta, then |f(x) - f(c)| < epsilon. This definition implies that the left-hand limit and right-hand limit of f(x) at c must be equal.

What is the epsilon-delta definition of continuity?

  1. For every epsilon > 0, there exists a delta > 0 such that if 0 < |x - c| < delta, then |f(x) - f(c)| < epsilon.

  2. For every epsilon > 0, there exists a delta > 0 such that if 0 < |x - c| < delta, then |f(x) - L| < epsilon, where L is the limit of f(x) at c.

  3. For every epsilon > 0, there exists a delta > 0 such that if 0 < |x - c| < delta, then |f(x) - f(c)| > epsilon.

  4. For every epsilon > 0, there exists a delta > 0 such that if 0 < |x - c| < delta, then |f(x) - L| > epsilon, where L is the limit of f(x) at c.


Correct Option:
Explanation:

The epsilon-delta definition of continuity states that a function f(x) is continuous at a point c if for every epsilon > 0, there exists a delta > 0 such that if 0 < |x - c| < delta, then |f(x) - f(c)| < epsilon.

Which of the following functions is continuous at x = 0?

  1. f(x) = x^2

  2. f(x) = 1/x

  3. f(x) = |x|

  4. f(x) = sin(x)


Correct Option:
Explanation:

The function f(x) = x^2 is continuous at x = 0 because its limit at x = 0 is 0, which is equal to the value of the function at x = 0.

Which of the following functions is discontinuous at x = 0?

  1. f(x) = x^2

  2. f(x) = 1/x

  3. f(x) = |x|

  4. f(x) = sin(x)


Correct Option:
Explanation:

The function f(x) = 1/x is discontinuous at x = 0 because its limit at x = 0 does not exist.

What is the type of discontinuity of the function f(x) = 1/x at x = 0?

  1. Removable discontinuity

  2. Jump discontinuity

  3. Infinite discontinuity

  4. Oscillating discontinuity


Correct Option:
Explanation:

The function f(x) = 1/x has an infinite discontinuity at x = 0 because the limit of the function at x = 0 does not exist and the function approaches infinity as x approaches 0.

Which of the following functions has a jump discontinuity at x = 1?

  1. f(x) = x^2

  2. f(x) = 1/x

  3. f(x) = |x|

  4. f(x) = sin(x)


Correct Option:
Explanation:

The function f(x) = |x| has a jump discontinuity at x = 1 because the left-hand limit and right-hand limit of the function at x = 1 are not equal.

Which of the following functions has an oscillating discontinuity at x = 0?

  1. f(x) = x^2

  2. f(x) = 1/x

  3. f(x) = |x|

  4. f(x) = sin(1/x)


Correct Option:
Explanation:

The function f(x) = sin(1/x) has an oscillating discontinuity at x = 0 because the limit of the function at x = 0 does not exist and the function oscillates between -1 and 1 as x approaches 0.

Which of the following statements is true about the continuity of a function on an interval?

  1. A function is continuous on an interval if it is continuous at every point in the interval.

  2. A function is continuous on an interval if it is continuous at every rational number in the interval.

  3. A function is continuous on an interval if it is continuous at every irrational number in the interval.

  4. A function is continuous on an interval if it is continuous at every point except for a finite number of points.


Correct Option:
Explanation:

A function is continuous on an interval if it is continuous at every point in the interval. This means that the function has no breaks or jumps in its graph on the interval.

Which of the following functions is continuous on the interval [0, 1]?

  1. f(x) = x^2

  2. f(x) = 1/x

  3. f(x) = |x|

  4. f(x) = sin(x)


Correct Option:
Explanation:

The function f(x) = x^2 is continuous on the interval [0, 1] because it is continuous at every point in the interval.

Which of the following functions is discontinuous on the interval [0, 1]?

  1. f(x) = x^2

  2. f(x) = 1/x

  3. f(x) = |x|

  4. f(x) = sin(x)


Correct Option:
Explanation:

The function f(x) = 1/x is discontinuous on the interval [0, 1] because it is discontinuous at x = 0.

Which of the following statements is true about the continuity of a function on a closed interval?

  1. A function is continuous on a closed interval if it is continuous at every point in the interval, including the endpoints.

  2. A function is continuous on a closed interval if it is continuous at every point in the interval, except for the endpoints.

  3. A function is continuous on a closed interval if it is continuous at every rational number in the interval, including the endpoints.

  4. A function is continuous on a closed interval if it is continuous at every irrational number in the interval, including the endpoints.


Correct Option:
Explanation:

A function is continuous on a closed interval if it is continuous at every point in the interval, including the endpoints. This means that the function has no breaks or jumps in its graph on the interval, including at the endpoints.

Which of the following functions is continuous on the closed interval [0, 1]?

  1. f(x) = x^2

  2. f(x) = 1/x

  3. f(x) = |x|

  4. f(x) = sin(x)


Correct Option:
Explanation:

The function f(x) = x^2 is continuous on the closed interval [0, 1] because it is continuous at every point in the interval, including the endpoints.

Which of the following functions is discontinuous on the closed interval [0, 1]?

  1. f(x) = x^2

  2. f(x) = 1/x

  3. f(x) = |x|

  4. f(x) = sin(x)


Correct Option:
Explanation:

The function f(x) = 1/x is discontinuous on the closed interval [0, 1] because it is discontinuous at x = 0.

Which of the following statements is true about the continuity of a function on an open interval?

  1. A function is continuous on an open interval if it is continuous at every point in the interval.

  2. A function is continuous on an open interval if it is continuous at every rational number in the interval.

  3. A function is continuous on an open interval if it is continuous at every irrational number in the interval.

  4. A function is continuous on an open interval if it is continuous at every point except for a finite number of points.


Correct Option:
Explanation:

A function is continuous on an open interval if it is continuous at every point in the interval. This means that the function has no breaks or jumps in its graph on the interval.

Which of the following functions is continuous on the open interval (0, 1)?

  1. f(x) = x^2

  2. f(x) = 1/x

  3. f(x) = |x|

  4. f(x) = sin(x)


Correct Option:
Explanation:

The function f(x) = x^2 is continuous on the open interval (0, 1) because it is continuous at every point in the interval.

Which of the following functions is discontinuous on the open interval (0, 1)?

  1. f(x) = x^2

  2. f(x) = 1/x

  3. f(x) = |x|

  4. f(x) = sin(x)


Correct Option:
Explanation:

The function f(x) = 1/x is discontinuous on the open interval (0, 1) because it is discontinuous at x = 0.

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