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CBSE Questions for Class 12 Commerce Maths Relations And Functions Quiz 4 - MCQExams.com

If f:(3,6)(1,3) is a function defined by f(x)=x[x3] ( where [.] denotes the greatest integer function ), then f1(x)=
  • x1
  • x+1
  • x
  • none of these
Let g(x)=1+x[x] and f(x)={1x<00x=01x>0 Then for all  x,f{g(x)} is equal to 
  • x
  • 1
  • f(x)
  • g(x)
The inverse of the function f(x)=log2(x+x2+1) is
  • 2x+2x
  • 2x+2x2
  • 2x2x2
  • 2x2x2
If f:{1,2,3,...}{0,±1,±2,...} is defined by
y=f(x)={x2 if x is even (x1)2, if x is odd , then f1(100) is
  • Function is not invertible as it is not onto
  • 199
  • 201
  • 200
If f(y)=y1y2; g(y)=y1+y2 then (fog)y is equal to
  • y1y2
  • y1+y2
  • y
  • 2f(x)
If f(x)=(x1)+(x+1) and
g(x)=f{f(x)} then g(3)
  • equals 1
  • equals 0
  • equals 3
  • equals 4
If f(x)=x+tanx and g1=f then g(x) equals
  • 12+[g(x)+x]2
  • 11+[g(x)x]2
  • 12+[g(x)x]2
  • 12[g(x)x]2
Let f:[4,)[4,) be a function defined by f(x)=5x(x4), then f1(x) is
  • 24+log5x
  • 2+4+log5x
  • (15)x(x4)
  • None of these
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Assertion is incorrect but Reason is correct
Let f:NY  be a function defined as f(x)=4x+3 where Y={yN:y=4x+3} for some xN such that f is invertible then its inverse is
  • g(y)=4+y+34
  • g(y)=2y34
  • g(y)=3y+43
  • g(y)=y34
If f(x)={x2x0xx<0
then (fof)(x) is given by
  • x2 for x0 and x for x<0
  • x4 for x0 and x2 for x<0
  • x4 for x0 and x2 for x<0
  • x4 for x0 and x for x<0
If f(x)=3x+25x3 then
  • f1(x)=f(x)
  • f1(x)=f(x)
  • fo(f(x))=x
  • f1(x)=119f(x)
Let f:RR be defined as f(x)=x2+5x+9 then f1(8) equals to 
  • {5+202,5212}
  • {5+212,5212}
  • {5212,2152}
  • Does not exist.
Which of the following functions have inverse defined on the ranges
  • f(x)=x2,x R
  • f(x)=x3,x R
  • f(x)=ex,x R
  • f(x)=sinx, 0<x<2π
Let f(x)=tan x, xϵ[π2,π2] and g(x)=1x2 Determine gof(1).
  • 1
  • 0
  • -1
  • not defined
Find ϕ[Ψ(x)] and Ψ[ϕ(x)] if ϕ(x)=x2+1 and Ψ(x)=3x.
  • Ψ[ϕ(x)]=3x2+1.
  • ϕ[Ψ[x]]=32x+1
  • Ψ[ϕ(x)]=3x3+1.
  • ϕ[Ψ[x]]=3x+1
The inverse of the functionf(x)=(1(x5)3)1/5is 
  • 5(1x5)1/3
  • 5+(1x5)1/3
  • 5+(1+x5)1/3
  • 5(1+x5)1/3
If f(x)=ax+bcx+d and (fof)x=x, then d=?
  • a
  • a
  • b
  • b
The inverse of the function logex  is 
  • 10x.
  • ex
  • 10e.
  • xe.
The total number of injective mappings from a set with m elements to a set with n elements,mn, is
  • mn
  • nm
  • n!(nm)!
  • n!
If A={a,b,c,d},B={1,2,3} find whether or not the following sets of ordered pairs are relations from A to B or not.
R1={(a,1),(a,3)}
R2={(a,1),(c,2),(d,1)}
R3={(a,1),(b,2),(3,c)}.
  • R1 R2 are relations but R3 is not a relation.
  • R1 R3 are relations but R2 is not a relation.
  • All are relations
  • none of these
Are the following sets of ordered pairs functions? If so, examine whether the mapping is surjective or injective :
{(x, y): x is a person, y is the mother of x}
  • injective (one- one ) and surjective (into)
  • injective (one- one ) and not surjective (into)
  • not injective (one- one ) and surjective (into)
  • not injective (one- one ) and not surjective (into)
Given f(x)=log(1+x1x) and g(x)=3x+x31+3x2,fog(x) equals
  • f(x)
  • 3f(x)
  • [f(x)]3
  • none of these
Let R be a relation from a set A to a set B,then
  • R=AB
  • R=AB
  • RA×B
  • RB×A
If A={a,b,c,d},B={p,q,r,s}, then which of the following are relations from A to B
  • R1={(a,p),(b,r),(c,s)}
  • R2={(q,b),(c,s),(d,r)}
  • R3={(a,p),(a,q),(d,p),(c,r),(b,r)}
  • R4={(a,p),(q,a),(b,s),(s,b)}
If f:RR and g:RR are functions defined by f(x)=3x1;g(x)=x+6, then the value of (gf1)(2009) is 
  • 26
  • 29
  • 16
  • 15
If X={1,2,3,4,5},Y={1,3,5,7,9} determine which of the following sets are mappings, relations or neither from A to B:
(i)F={(x,y)y=x+2,xX,yY}
  • It is clearly a one-one onto mapping i.e. a bijection. It is also a relation.
  • It is clearly a many-one onto mapping. It is also a relation.
  • It is clearly a one-one but not onto mapping. It is also a relation.
  • It is not a mapping but a relation
Let f:[2,)[1,)defined by f(x)=2x44x2 and g:[π2,π]A defined by g(x)=sinx+4sinx2 be two invertible functions, then
f1(x) is equal to
  • 2+4log2x
  • 2+4+log2x
  • 24+log2x
  • None of these
If f0(x)=x(x+1) and fn+1=f0fn(x) for n=0,1,2, then fn(x) is
  • x(n+1)x+1
  • f0(x)
  • nxnx+1
  • xnx+1
Let f(x)=x22x and g(x)=f(f(x)1)+f(5f(x)), then
  • g(x)<0,xR
  • g(x)<0 for some xR
  • g(x)0 for some xR
  • g(x)0,xR
If f(x)={2x+3x1a2x+1x>1, then the values of a for which f(x) is injective. 
  • 3
  • 1
  • 0
  • none of these
Which of the functions defined below are NOT one-one function(s) 
  • f(x)=5(x2+4),(xR)
  • g(x)=2x+1x
  • h(x)=ln(x2+x+1),(xR)
  • f(x)=ex
If g(x)=1+x and f(g(x))=3+2x+x, then f(x)=
  • 1+2x2
  • 2+x2
  • 1+x
  • 2+x
Let X={1,2,3,4} and Y={1,2,3,4}. Which of the following is a relation from X to Y.
  • R1={(x,y)|y=2+x,xX,yY}
  • R2={(1,1),(2,1),(3,3),(4,3),(5,5)}
  • R3={(1,1),(1,3),(3,5),(3,7),(5,7)}
  • R4={(1,3),(2,5),(2,4),(7,9)}
Find inverse f(x)=loge(x+x2+1)
  • sinh(x)
  • cosh(x)
  • tanh(x)
  • coth(x)
Let f : {x,y,z} {a,b,c} be a one-one function. It is known that only one of the following statment is true, and only one such function exists :

find the function f (as ordered pair).(i) f(x) b
(i) f(y) = b

(ii) f(z) a
  • {(x,b), (y,a), (z,c)}
  • {(x,a), (y,b), (z,c)}
  • {(x,b), (y,c), (z,a)}
  • {(x,c), (y,a), (z,b)}
Suppose f and g both are linear function with f(x)=2x+1  and f(g(x))=6x7 then slope of line y=g(x) is
  • 3
  • 3
  • 6
  • 2
 from the given statement N denotes the natural number and W denotes the whole number, so which statement in the following is correct
  • N=W
  • N W
  • W N
  • N W
If f(x)={x+1,ifx15x2ifx>1,g(x)={xifx12xifx>1

and x(1,2), then g(f(x)) is equal to
  • x2+3
  • x23
  • 5x2
  • 1x
If g(x)=2x+1 and h(x)=4x2+4x+7, find a function f such that fog=h
  • f(x)=x36
  • f(x)=x2+6
  • f(x)=x26
  • f(x)=(2x+1)2+6
Let X={1,2,3,4} and Y={1,3,5,7,9}. Which of the following is relations from X to Y
  • R1={(x,y)|y=2x+1,xX,yY}
  • R2={(1,1),(2,1),(3,3),(4,3),(5,5)}
  • R3={(1,1),(1,3),(3,5),(3,7),(5,7)}
  • R4={(1,3),(2,5),(2,4),(7,9)}
Which of the following are two distinct linear functions which map the interval [1,1] onto [0,2]
  • f(x)=1+x or 1x
  • f(x)=1+2x or 1x
  • f(x)=1+x or 12x
  • f(x)=1+x or 2x
If f(x)=ln1+x1x and g(x)=3x+x31+3x2, then f[g(x)] equals.

  • f(x)
  • [f(x)]3
  • 3f(x)
  • f(x)2
Let f(x)=e3x,g(x)=logex,x>0, then fog(x) is
  • 3x
  • x3
  • log103x
  • log3x
f(x)>x;xϵR. The equation f(f(x))x=0 has
  • Atleast one real root
  • More than one real root
  • No real root if f(x) is a polynomial & one real root if f(x) is not a polynomial
  • No real root at all
If f:RR,f(x)=(x+1)2 and g:RR,g(x)=x2+1 then (fog)(3) is equal to
  • 121
  • 144
  • 112
  • 11
If f(x)=|x1| and g(x)=sinx, then (fog)(x) equals
  • sin|x1|
  • |sinx2cosx2|
  • |sinx+cosx|
  • |sinx2+cosx2|
If f(x)=logx, g(x)=x3, then f[g(a)]+f[g(b)] equals
  • f[g(a)+g(b)]
  • 3f(ab)
  • g[f(ab)]
  • g[f(a)+f(b)]
If f(x)=x3 and g(x)=sin2x, then
  • g[f(1)]=1
  • f(g(π/12)=1/8
  • gf(2)=sin2
  • none of these
If f(x)=(axn)1/n, where  nN, then f{f(x)} equals
  • 0
  • x
  • xn
  • none of these
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Practice Class 12 Commerce Maths Quiz Questions and Answers