Q261.Let R be the set of all real numbers. Then f:R→ → →R is not a mapping if it is defined by:
Correct answer: f (x) = log x
Q262.Let R, be the set of real number, aRb if and only if 1 2 a b − ≥ − ≥ any defined by is a relation then the relation R is:
Correct answer: Symmetric and transitive but not reflexive
Q263.A relation R in the set of natural numbers defined by aRb, if a and b are Co-prime, then R is
Correct answer: an equivalence relation
Q264.Let R be a relation of the set of natural numbers N be defined by (()) { { } } x,y: x,y N,2x y 41 ∈ + = ∈ + = ∈ + = ∈ + = then R is
Correct answer: None of these
Q265.If A={x:f(x)=0} and B={x:g(x)=0}, then A∩ ∩ ∩B will be the set of roots of equation
Correct answer: () () 2 2 0 f x g x + =
Q266.Root(s) of the equation 9x2 –18|x|+5=0 belonging to the domain of function (())) (((()))) 2 log 2 = − − = − − = − − = − − f x x x is (are)–
Correct answer: −5/3
Q267.A and B are two independent sets then P(Ac ∩ ∩B) is equal to
Correct answer: P(Ac/) P(B)
Q268.If f '(x) =2x∀ ∀ ∀x and f (0)=0 then the value of f(2) will be
Correct answer: 4
Q269.If f(x) = loge (loge x), then f'
Correct answer: 1/e
Q270.If the set A has p elements and set B has q elements, then the number of elements in A×B is
Correct answer: pq
Q271.If f: R→ → →R and g: R→ → →R are two mappings defined as f(x) = x2 and g(x) = x2 +2, then
Correct answer: fog≠ gof
Q272.Let A, B, C be three sets, then (A – B) ∩ ∩ ∩(A – C) is equal to
Correct answer: () − ∪ A B C
Q273.In a city, 20% of the population travel by car, 50% travel by bus and 10% travel by both car and bus. Then persons travelling by car or bus is
Correct answer: 60%
Q274.Following are the relations in a set of real numbers. What of them is equivalence relation?
Correct answer: | | | | ⇔ = aRb a b
Q275.A relation R is defined on the set of positive integers N by a R b if ab = ba. Then R is
Correct answer: an equivalence relation
Q276.If 2 (), 3 3 + = ≠ − x f x x x then 1 () − f x is equal to
Correct answer: 3 2 1 x + −
Q277.If the equation a b 1 x a x b + = − − has two roots equal in magnitude and opposite in sign, then the value of a + b is
Correct answer: 0
Q278.If the roots of the equation ax2 +bx+c=0 are of the form 1 k + and 2 1 k + then the value of (a+b+c)2 is
Correct answer: b2/–4ac
Q279.Range of the function (()) f(x) 1/ 2 sin3x, x = − −∞ < < ∞ = − −∞ < < ∞ = − −∞ < < ∞ = − −∞ < < ∞ is
Correct answer: 1,1 3
Q280.If,,, a b c d are positive real number such that a + b + c + d = 2, then M = (a + b) (c + d) satisfies the following relation
Correct answer: 0 1 M ≤