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:

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?