Class 12 Math: Relations And Functions

Class 12 Math

ID: 292 Type: Mcq Source: AISSCE(Board Exam) Year: 2025
Question 1: For real x, let \(f(x)=x^{3}+5x+1\). Then:
  • A. f is one-one but not onto on R
  • B. f is onto on R but not one-one
  • C. f is one-one and onto on R
  • D. f is neither one-one nor onto on R
ID: 298 Type: Mcq Source: AISSCE(Board Exam) Year: 2025
Question 2: If \(f:N\rightarrow W\) is defined as \(f(n)=\begin{cases}\frac{n}{2},&if~n~is~even\\ 0,&if~n~is~odd\end{cases}\), then f is:
  • A. injective only
  • B. surjective only
  • C. a bijection
  • D. neither surjective nor injective
ID: 470 Type: Mcq Source: AISSCE(Board Exam) Year: 2024
Question 3: A function \(f:R_{+}\rightarrow R\) (where \(R_{+}\) is the set of all non-negative real numbers) defined by \(f(x)=4x+3\) is:
  • A. one-one but not onto
  • B. onto but not one-one
  • C. both one-one and onto
  • D. neither one-one nor onto
ID: 489 Type: Mcq Source: AISSCE(Board Exam) Year: 2024
Question 4: Let \(f:R_{+}\rightarrow[-5,\infty)\) be defined as \(f(x)=9x^{2}+6x-5\), where \(R_{+}\) is the set of all non-negative real numbers. Then, f is:
  • A. one-one
  • B. onto
  • C. bijective
  • D. neither one-one nor onto
ID: 507 Type: Mcq Source: AISSCE(Board Exam) Year: 2024
Question 5: Let \(R_{+}\) denote the set of all non-negative real numbers. Then the function \(f:R_{+}\rightarrow R_{+}\) defined as \(f(x)=x^{2}+1\) is :
  • A. one-one but not onto
  • B. onto but not one-one
  • C. both one-one and onto
  • D. neither one-one nor onto
ID: 542 Type: Mcq Source: AISSCE(Board Exam) Year: 2024
Question 6: A function \(f:\mathbb{R}\rightarrow\mathbb{R}\) defined as \(f(x)=x^{2}-4x+5\) is:
  • A. injective but not surjective.
  • B. surjective but not injective.
  • C. both injective and surjective.
  • D. neither injective nor surjective.
ID: 238 Type: Assertion-reason Source: AISSCE(Board Exam) Year: 2025
Question 7:

Assertion (A) : Let \(\mathbb{Z}\) be the set of integers. A function \(f: \mathbb{Z} \to \mathbb{Z}\) defined as \(f(x)=3x-5, \forall x \in \mathbb{Z}\) is a bijective function.

Reason (R) : A function is a bijective function if it is both surjective and injective.

ID: 447 Type: Very short (VSA) Source: AISSCE(Board Exam) Year: 2025
Question 8: Let \(f:A\rightarrow B\) be defined by \(f(x)=\frac{x-2}{x-3}\) ' where \(A=R-\{3\}\) and \(B=R-\{1\}\). Discuss the bijectivity of the function.
ID: 662 Type: Very short (VSA) Source: AISSCE(Board Exam) Year: 2024
Question 9: A relation R on set \(A=\{-4,-3,-2,-1,0,1,2,3,4\}\) be defined as \(R=\{(x,y):x+y\) is an integer divisible by 2). Show that R is an equivalence relation. Also, write the equivalence class.
ID: 266 Type: Short (SA) Source: AISSCE(Board Exam) Year: 2025
Question 10: Let R be a relation defined over N, where N is set of natural numbers, defined as

"\(m\)R\(n\) if and only if \(m\) is a multiple of \(n\), \(m, n\in N\)."

Find whether R is reflexive, symmetric and transitive or not.

ID: 370 Type: Short (SA) Source: AISSCE(Board Exam) Year: 2025
Question 11: If \(f:R^{+}\rightarrow R\) is defined as \(f(x)=\log_{a} x\) (\(a > 0\) and \(a\ne1)\), prove that f is a bijection. (\(R^{+}\) is a set of all positive real numbers.)
ID: 371 Type: Short (SA) Source: AISSCE(Board Exam) Year: 2025
Question 12: Let \(A=\{1,2,3\}\) and \(B=\{4,5,6\}\). A relation R from A to B is defined as \(R=\{(x,y):x+y=6, x \in A, y\in B\}\).
  • Write all elements of R.
  • Is R a function? Justify.
  • Determine domain and range of R.
  • ID: 435 Type: Short (SA) Source: AISSCE(Board Exam) Year: 2025
    Question 13: A student wants to pair up natural numbers in such a way that they satisfy the equation \(2x+y=41\), \(x, y\in N\). Find the domain and range of the relation. Check if the relation thus formed is reflexive, symmetric and transitive. Hence, state whether it is an equivalence relation or not.
    ID: 436 Type: Short (SA) Source: AISSCE(Board Exam) Year: 2025
    Question 14: Show that the function \(f:N\rightarrow N\), where N is a set of natural numbers, given by \(f(n) = \begin{cases}n-1,&if~n~is~even\\ n+1,&if~n~is~odd\end{cases}\) is a bijection.
    ID: 454 Type: Short (SA) Source: AISSCE(Board Exam) Year: 2025
    Question 15: Show that the function \(f:R\rightarrow R\) defined by \(f(x)=4x^{3}-5\), \(\forall x\in R\) is one-one and onto.
    ID: 455 Type: Short (SA) Source: AISSCE(Board Exam) Year: 2025
    Question 16: Let R be a relation defined on a set N of natural numbers such that \(R=\{(x,y)\): xy is a square of a natural number, \(x, y\in N\}\). Determine if the relation R is an equivalence relation.
    ID: 596 Type: Short (SA) Source: AISSCE(Board Exam) Year: 2024
    Question 17: A relation R on set \(A=\{1,2,3,4,5\}\) is defined as \(R=\{(x,y):|x^{2}-y^{2}|<8\}\). Check whether the relation R is reflexive, symmetric and transitive.
    ID: 611 Type: Short (SA) Source: AISSCE(Board Exam) Year: 2024
    Question 18: A function \(f\) is defined from \(R\rightarrow R\) as \(f(x)=ax+b\), such that \(f(1)=1\) and \(f(2)=3\). Find function \(f(x)\). Hence, check whether function \(f(x)\) is one-one and onto or not.
    ID: 647 Type: Long (LA) Source: AISSCE(Board Exam) Year: 2024
    Question 19: Let \(A=R-\{5\}\) and \(B=R-\{1\}\). Consider the function \(f:A\rightarrow B\), defined by \(f(x)=\frac{x-3}{x-5}\). Show that f is one-one and onto.
    ID: 648 Type: Long (LA) Source: AISSCE(Board Exam) Year: 2024
    Question 20: Show that a function \(f:R\rightarrow R\) defined by \(f(x)=\frac{2x}{1+x^{2}}\) is neither one-one nor onto. Further, find set A so that the given function \(f:R\rightarrow A\) becomes an onto function.
    ID: 651 Type: Long (LA) Source: AISSCE(Board Exam) Year: 2024
    Question 21: A relation R is defined on \(N\times N\) (where N is the set of natural numbers) as: \((a, b)~R~(c,d)\Leftrightarrow a-c=b-d\) Show that R is an equivalence relation.
    ID: 652 Type: Long (LA) Source: AISSCE(Board Exam) Year: 2024
    Question 22: Check whether the relation S in the set of real numbers R defined by \(S=\{(a,b)\): where \(a-b+\sqrt{2}\) is an irrational number is reflexive, symmetric or transitive.
    ID: 191 Type: Case Study Year: 2025
    Question 23:

    A school is organizing a debate competition with participants as speakers \(S = \{S_1, S_2, S_3, S_4\}\) and these are judged by judges \(J = \{J_1, J_2, J_3\}\). Each speaker can be assigned one judge. Let R be a relation from set S to J defined as \(R=\{(x,y)\): speaker \(x\) is judged by judge \(y, x\in S, y\in J\}\).

    Based on the above answer the following:

    (i) How many relations can be there from S to J? (1 mark)

    (ii)A student identifies a function from S to J as \(f=\{(S_{1},J_{1}), (S_2, J_2), (S_{3},J_{2}), (S_{4},J_{3}))\). Check if it is bijective. (1 mark)

    (iii)(a) How many one-one functions can be there from set S to set J? (2 marks)

    OR

    (iii)(b) Another student considers a relation \(R_{1}=\{(S_{1},S_{2}), (S_2, S_4)\}\) in set S. Write minimum ordered pairs to be included in \(R_{1}\) so that \(R_{1}\) is reflexive but not symmetric. (2 marks)

    ID: 216 Type: Case Study Source: AISSCE(Board Exam) Year: 2025
    Question 24: A class-room teacher is keen to assess the learning of her students the concept of "relations" taught to them. She writes the following five relations each defined on the set \(\mathbf{A = \{1, 2, 3\}}\):\[\begin{aligned} R_1 &= \{(2, 3), (3, 2)\} \\ R_2 &= \{(1, 2), (1, 3), (3, 2)\} \\ R_3 &= \{(1, 2), (2, 1), (1, 1)\} \\ R_4 &= \{(1, 1), (1, 2), (3, 3), (2, 2)\} \\ R_5 &= \{(1, 1), (1, 2), (3, 3), (2, 2), (2, 1), (2, 3), (3, 2)\} \end{aligned}\]The students are asked to answer the following questions about the above relations:(i) Identify the relation which is reflexive, transitive but not symmetric.(ii) Identify the relation which is reflexive and symmetric but not transitive.(iii) (a) Identify the relations which are symmetric but neither reflexive nor transitive.\[\mathbf{OR}\](iii) (b) What pairs should be added to the relation \(\mathbf{R_2}\) to make it an equivalence relation?
    ID: 277 Type: Case Study Source: AISSCE(Board Exam) Year: 2025
    Question 25: A school is organizing a debate competition with participants as speakers \(S = \{S_1, S_2, S_3, S_4\}\) and these are judged by judges \(J = \{J_1, J_2, J_3\}\). Each speaker can be assigned one judge. Let R be a relation from set S to J defined as \(R=\{(x,y)\): speaker \(x\) is judged by judge \(y, x\in S, y\in J\}\).

    Based on the above answer the following:

    (i) How many relations can be there from S to J? (1 mark)

    (ii)A student identifies a function from S to J as \(f=\{(S_{1},J_{1}), (S_2, J_2), (S_{3},J_{2}), (S_{4},J_{3}))\). Check if it is bijective. (1 mark)

    (iii)(a) How many one-one functions can be there from set S to set J? (2 marks)

    OR

    (iii)(b) Another student considers a relation \(R_{1}=\{(S_{1},S_{2}), (S_2, S_4)\}\) in set S. Write minimum ordered pairs to be included in \(R_{1}\) so that \(R_{1}\) is reflexive but not symmetric. (2 marks)