Sets, Relations and Functions · Mathematics · NDA

Let $A = \{x \in \mathbb{R} : -1 <x <1\}$. Which of the following is/are bijective functions from A to itself?

1. $f(x) = x|x|$

2. $g(x) = \cos(\pi x)$

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Let $R$ be a relation on the open interval $(-1, 1)$ and is given by $R = \{(x, y) : |x + y| < 2\}$. Then which one of the following is correct?

For any three non-empty sets $A, B, C$, what is $$(A \cup B - \{(A - B) \cup (B - A) \cup (A \cap B)\})$$ equal to?

Let $A = \{1, 2, 3, 4, 5\}$ and $B = \{6, 7\}$. What is the number of onto functions from $A$ to $B$?

The Cartesian product A × A has 16 elements among which are (0, 2) and (1, 3). Which of the following statements is/are correct?

1. It is possible to determine set A.

2. A × A contains the element (3, 2).

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Let A = {1, 2, 3, ..., 20}. Define a relation R from A to A by R = {(x, y) : 4x - 3y = 1}, where x, y ∈ A. Which of the following statements is/are correct?

1. The domain of R is {1, 4, 7, 10, 13, 16).

2. The range of R is {1, 5, 9, 13, 17).

3. The range of R is equal to codomain of R.

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Consider the following statements: 

1. The relation f defined by $f(x)= \begin{cases}x^3, & 0 \leq x \leq 2 \\ 4 x, & 2 \leq x \leq 8\end{cases}$ is a function.

2. The relation g defined by $g(x)= \begin{cases}x^2, & 0 \leq x \leq 4 \\ 3 x, & 4 \leq x \leq 8\end{cases}$ is a function.

Which of the statements given above is/are correct?

Consider the following statements 

1. A = (A ∪ B) ∪ (A - B),

2. A ∪ (B - A) = (A ∪ B)

3. B = (A ∪ B) - (A - B)

Which of the statements given above are correct?

Consider the following statements :

1. If f is the subset of Z × Z defined by f = {(xy, x − y); x, y ∈ Z}, then f is a function from Z to Z.

2. If f is the subset of N × N defined by f = {(xy, x + y); x, y ∈ N}, then f is a function from N to N.

Which of the statements given above is/are correct?

Consider the following statements :

1. The set of all irrational numbers between $\sqrt{2}$ and $\sqrt{5}$ is an infinite set.

2. The set of all odd integers less than 100 is a finite set.

Which of the statements given above is/are correct?

Let A = {7, 8, 9, 10, 11, 12, 13; 14, 15, 16} and let f ∶ A → N be defined by f(x) = the highest prime factor of x.

How many elements are there in the range of f?

Let R be a relation from N to N defined by R = {(x, y): x, y ∈ N and x2 = y³}. Which of the following are not correct?

1. (x, x) ∈ R for all x ∈ N

2. (x, y) ∈ R ⇒ (y, x) ∈ R

3. (x, y) ∈ R and (y, z) ∈ R ⇒ (x, z) ∈ R

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Consider the following :

1. A ∩ B = A ∩ C ⇒ B = C

2. A ∪ B = A ∪ C ⇒ B = C

Which of the above is/are correct ?

How many received medals in exactly two of the three sports ?

How many received medals in at least two of three sports ?

How many received medals in exactly one of three sports ?

Consider the following statements in respect of two non-empty sets A and B :

1. x ∉ (A ∪ B) ⇒ x ∉ A or x ∉ B

2. x ∉ (A ∩ B) ⇒ x ∉ A and x ∉ B

Which of the above statements is/are correct?

Consider the following statements in respect of two non-empty sets A and B :

1. A ∪ B = A ∩ B if A = B

2. A Δ B = ϕ  if A = B

Which of the above statements is/are correct ?

Consider the following statements in respect of the relation R in the set IN of natural numbers defined by xRy if x² - 5xy + 4y² = 0 :

1. R is reflexive

2. R is symmetric

3. R is transitive

Which of the above statements is /are correct ?

Consider the following statements in respect of any relation R on a set A :

1. If R is reflexive, then R^-1 is also reflexive

2. If R is symmetric, then R^-1 is also symmetric

3. If R is transitive, then R^-1 is also transitive

Which of the above statements are correct?

Consider the following statements in respect of sets:

1. The union over the intersection of sets is distributive.

2. The complement of the union of two sets is equal to the intersection of their complements.

3. If the difference between the two sets is equal to the empty set, then the two sets must be equal.

Which of the above statements are correct?

Consider the following statements in respect of relations and functions:

1. All relations are functions but all functions are not relations.

2. A relation from A to B is a subset of Cartesian product A × B.

3. A relation in A is a subset of Cartesian product A × A.

Which of the above statements are correct?

Consider the following statements:

1. A = {1, 3, 5} and B = {2, 4, 7} are equivalent sets.

2. A = {1, 5, 9} and B = {1, 5, 5, 9, 9} are equal sets.

Which of the above statements is/are correct?

Consider the following statements:

1. The null set is a subset of every set.

2. Every set is a subset of itself.

3. If a set has 10 elements, then its power set will have 1024 elements.

Which of the above statements are correct?