Sets and Functions

Description: This quiz covers the fundamental concepts of sets and functions. It assesses your understanding of set operations, properties of functions, and their applications in various mathematical contexts.
Number of Questions: 15
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Tags: sets functions set operations function properties applications of functions
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Given the sets A = {1, 3, 5} and B = {2, 4, 6}, what is the union of A and B?

  1. {1, 2, 3, 4, 5, 6}

  2. {1, 3, 5, 2, 4, 6}

  3. {1, 2, 3, 4, 5}

  4. {1, 3, 5, 6}


Correct Option: A
Explanation:

The union of two sets A and B, denoted as A ∪ B, is the set of all elements that are in either A or B. Therefore, the union of A = {1, 3, 5} and B = {2, 4, 6} is {1, 2, 3, 4, 5, 6}.

What is the intersection of the sets A = {1, 2, 3, 4, 5} and B = {3, 4, 5, 6, 7}?

  1. {1, 2}

  2. {3, 4, 5}

  3. {1, 2, 3, 4, 5, 6, 7}

  4. {6, 7}


Correct Option: B
Explanation:

The intersection of two sets A and B, denoted as A ∩ B, is the set of all elements that are in both A and B. Therefore, the intersection of A = {1, 2, 3, 4, 5} and B = {3, 4, 5, 6, 7} is {3, 4, 5}.

Which of the following is a function?

  1. {(1, 2), (2, 3), (3, 4)}

  2. {(1, 2), (2, 3), (3, 2)}

  3. {(1, 2), (1, 3), (2, 4)}

  4. {(1, 2), (2, 3), (3, 4), (4, 5)}


Correct Option: A
Explanation:

A function is a relation that assigns to each element of a set a unique element of another set. In other words, each input value can only have one output value. Therefore, the relation {(1, 2), (2, 3), (3, 4)} is a function, while the other relations are not.

What is the domain of the function f(x) = sqrt(x - 1)?

  1. [0, ∞)

  2. [-1, ∞)

  3. [1, ∞)

  4. (-∞, 1]


Correct Option: C
Explanation:

The domain of a function is the set of all possible input values for which the function is defined. Since the expression sqrt(x - 1) is defined only for non-negative values of x - 1, the domain of f(x) = sqrt(x - 1) is [1, ∞).

What is the range of the function f(x) = 2x + 1?

  1. [-∞, ∞)

  2. [0, ∞)

  3. (-∞, 0]

  4. [-1, ∞)


Correct Option: A
Explanation:

The range of a function is the set of all possible output values that the function can produce. Since the function f(x) = 2x + 1 is a linear function with no restrictions on the input values, its range is the set of all real numbers, which is [-∞, ∞).

Which of the following functions is one-to-one?

  1. f(x) = x^2

  2. f(x) = |x|

  3. f(x) = sin(x)

  4. f(x) = cos(x)


Correct Option: C
Explanation:

A function is one-to-one if each input value corresponds to a unique output value. The function f(x) = sin(x) is one-to-one because for any two distinct input values x1 and x2, sin(x1) and sin(x2) are distinct.

Which of the following functions is onto?

  1. f(x) = x^2

  2. f(x) = |x|

  3. f(x) = sin(x)

  4. f(x) = cos(x)


Correct Option: D
Explanation:

A function is onto if every element in the range of the function is the output of at least one input value. The function f(x) = cos(x) is onto because for any value y in the range [-1, 1], there exists an input value x such that cos(x) = y.

What is the inverse function of f(x) = 2x + 1?

  1. f^-1(x) = (x - 1)/2

  2. f^-1(x) = (x + 1)/2

  3. f^-1(x) = 2x - 1

  4. f^-1(x) = -2x + 1


Correct Option: A
Explanation:

The inverse function of f(x) is the function that undoes the operation performed by f(x). To find the inverse function of f(x) = 2x + 1, we can solve for x in terms of y: y = 2x + 1. Subtracting 1 from both sides, we get y - 1 = 2x. Dividing both sides by 2, we get x = (y - 1)/2. Therefore, the inverse function of f(x) = 2x + 1 is f^-1(x) = (x - 1)/2.

Which of the following is an example of a composite function?

  1. f(x) = sin(x^2)

  2. f(x) = x^2 + 2x + 1

  3. f(x) = sqrt(x)

  4. f(x) = |x|


Correct Option: A
Explanation:

A composite function is a function that is formed by combining two or more simpler functions. The function f(x) = sin(x^2) is a composite function because it is formed by composing the sine function with the squaring function.

What is the composition of the functions f(x) = x^2 and g(x) = x + 1?

  1. h(x) = x^2 + 1

  2. h(x) = x^2 + 2x + 1

  3. h(x) = x^4 + 2x^2 + 1

  4. h(x) = x^4 + x^2 + 1


Correct Option: B
Explanation:

The composition of two functions f(x) and g(x), denoted as f∘g(x), is the function that is obtained by applying g(x) to the input of f(x). Therefore, the composition of f(x) = x^2 and g(x) = x + 1 is h(x) = f∘g(x) = f(g(x)) = f(x + 1) = (x + 1)^2 = x^2 + 2x + 1.

Which of the following is an example of a bijective function?

  1. f(x) = x^2

  2. f(x) = |x|

  3. f(x) = sin(x)

  4. f(x) = cos(x)


Correct Option: C
Explanation:

A bijective function is a function that is both one-to-one and onto. The function f(x) = sin(x) is bijective because it is both one-to-one (each input value corresponds to a unique output value) and onto (every element in the range of the function is the output of at least one input value).

What is the cardinality of the set A = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}?

  1. 5

  2. 10

  3. 15

  4. 20


Correct Option: B
Explanation:

The cardinality of a set is the number of elements in the set. The set A = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} contains 10 elements. Therefore, the cardinality of A is 10.

Which of the following sets is a subset of the set B = {1, 3, 5, 7, 9}?

  1. {1, 2, 3, 4, 5}

  2. {1, 3, 5}

  3. {2, 4, 6, 8}

  4. {0, 2, 4, 6, 8}


Correct Option: B
Explanation:

A subset of a set B is a set that contains only elements that are also in B. The set {1, 3, 5} is a subset of B because every element of {1, 3, 5} is also an element of B. The other sets are not subsets of B because they contain elements that are not in B.

What is the complement of the set A = {1, 3, 5} in the universal set U = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}?

  1. {2, 4, 6, 8, 10}

  2. {2, 4, 6, 8}

  3. {2, 3, 4, 6, 8, 9, 10}

  4. {2, 4, 6, 8, 9}


Correct Option: A
Explanation:

The complement of a set A in a universal set U is the set of all elements in U that are not in A. The complement of A = {1, 3, 5} in U = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} is {2, 4, 6, 8, 10}.

Which of the following is an example of a power set?

  1. {1, 2, 3}

  2. {1, {2, 3}, 4}

  3. {1, 2, {3, 4}}

  4. {{1, 2}, {3, 4}, {5, 6}}


Correct Option: D
Explanation:

The power set of a set A is the set of all subsets of A. The set {{1, 2}, {3, 4}, {5, 6}} is the power set of the set {1, 2, 3, 4, 5, 6} because it contains all possible subsets of {1, 2, 3, 4, 5, 6}.

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