Relation and Function Set-2

Test your knowledge on Relations And Functions from Mathematics, Class 12.

60

Minutes

40

Questions

1 / -0

Marking Scheme

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Questions in this Quiz

Q1: Let f:RRf : R \rightarrow R be defined by f(x)=3x25f(x) = 3x^2 – 5 and g:RRg : R \rightarrow R by g(x)=2x2+1g(x) = \frac{2}{x^2 + 1} then gofgof is

  • 4x230x+269x230x+26\frac{4x^2 - 30x + 26}{9x^2 - 30x + 26}

  • 4x239x2+6x26\frac{4x^2 - 3}{9x^2 + 6x - 26}

  • 4x2+2x39x230x+2\frac{4x^2 + 2x - 3}{9x^2 - 30x + 2}

  • 49x430x2+26\frac{4}{9x^4 - 30x^2 + 26}

Q2: If the set AA contains 5 elements and set BB contains 6 elements, then the number of one-one and onto mapping from AA to BB is

  • 720

  • 120

  • 0

  • None of these

Q3: Let f:f : \rightarrow be defined by f(x)={x, if x is rational;1x, if x is irrational}f(x) = \{x, \text{ if } x \text{ is rational} ; 1-x, \text{ if } x \text{ is irrational}\}. Then (fof)x(fof)x is

  • constant

  • 1+x1 + x

  • xx

  • None of these

Q4: Let f:[2,)Rf : [2, \infty) \rightarrow R be the function defined by f(x)=x24x+5f(x) = x^2 – 4x + 5, then the range of ff is

  • RR

  • [1,)[1, \infty)

  • [4,)[4, \infty)

  • [5,)[5, \infty)

Q5: Let f:RRf : R \rightarrow R be defined by f(x)={2x2:x>3;x2:1x3;3x:x<1}f(x) = \{2x^2 : x > 3; x^2 : 1 \leq x \leq 3; 3x : x < 1\}. Then f(1)+f(2)+f(4)f(– 1) + f(2) + f(4) is

  • 9

  • 14

  • 5

  • None of these

Q6: The relation RR is defined on the set of natural numbers as {(a,b):a=2b}\{(a, b) : a = 2b\}. Then, R1R^{-1} is given by

  • {(2,1),(4,2),(6,3),.}\{(2, 1), (4, 2), (6, 3),\ldots.\}

  • {(1,2),(2,4),(3,6),.}\{(1, 2), (2, 4), (3, 6), \ldots.\}

  • R1R^{-1} is not defiend

  • None of these

Q7: Let f:RRf : R \rightarrow R be a function defined by f(x)=exexex+exf(x) = \frac{e^{|x|}-e^{-x}}{e^{x}+e^{-x}} then f(x)f(x) is

  • one-one onto

  • one-one but not onto

  • onto but not one-one

  • None of these

Q8: Let g(x)=x24x5g(x) = x^2 – 4x – 5, then

  • gg is one-one on RR

  • gg is not one-one on RR

  • gg is bijective on RR

  • None of these

Q9: The function f:RRf : R \rightarrow R given by f(x)=x31f(x) = x^3 – 1 is

  • a one-one function

  • an onto function

  • a bijection

  • neither one-one nor onto

Q10: Let f:[0,)f : [0, \infty) \rightarrow be defined by f(x)=2x1+xf(x)=\frac{2 x}{1+x}, then ff is

  • one-one but not onto

  • onto but not one-one

  • both one-one and onto

  • neither one-one nor onto

...and 30 more questions.