Discrete Mathematics (3140708) MCQs

MCQs of Set Theory

Showing 21 to 30 out of 70 Questions
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21.

If f :ℝ→ℝ defined by f(x)=2x--x, then the value of f(-3) is _____.

(a)

-9
(b)

-3
(c)

9
(d)

3
Answer:

Option (d)

22.

For f :A→B, if R(f)=B then f is said to be which function?

(a)

one to one
(b)

injective
(c)

onto
(d)

bijective
Answer:

Option (c)

23.
f:ℕ→ℕ define as f(n)=n+2 is _____ function.
(a) one to one
(b) onto
(c) bijective
(d) none of these
Answer:

Option (a)

24.
f:ℝ→ℝ define as f(x)=2x+3 is _____ function.
(a) one to one only
(b) onto only
(c) bijective
(d) none of these
Answer:

Option (c)

25.

If f:ℝ→ℝ define as f(x)=sinx, ∀x∈ℝ then Range(f)=_______.

(a)

(-1, 1)
(b)

[-1, 1]
(c)

(0, 1)
(d)

[0, 1]
Answer:

Option (b)

26.
A function which is one-one and onto both is called _____ function.
(a) injective
(b) surjective
(c) bijective
(d) none of these
Answer:

Option (c)

27.
Which of the following is incorrect?
(a) (A∪B)'=A'∪B'
(b) (A∩B)'=A'∪B'
(c) (A∪B)'=A'∩B'
(d) A-(B∪C)=(A-B)∩(A-C)
Answer:

Option (a)

28.
Which of the following is correct?
(a) n(A∪B)+n(A∩B)=n(A)
(b) n(A∪B)+n(A∩B)=n(B)
(c) n(A∪B)+n(A∩B)=n(A)+n(B)
(d) n(A∪B)+n(A∩B)=n(A)-n(B)
Answer:

Option (c)

29.
Which of the following is incorrect?
(a) (A∪B)'=A'∩B'
(b) (A∩B)'=A'∪B'
(c) A-(B∪C)=(A-B)∩(A-C)
(d) A×(B∪C)=(A×B)∩(A×C)
Answer:

Option (d)

30.
If A={1,2,3,4} and B={a,b,c,d} then which of the following is not function from A to B?
(a) {(1,a),(2,b),(3,c),(4,d)}
(b) {(1,a),(2,a),(3,a),(4,a)}
(c) {(a,1),(b,2),(c,3),(d,4)}
(d) {(1,a),(2,a),(3,b),(4,b)}
Answer:

Option (c)

Showing 21 to 30 out of 70 Questions
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