Relations and Functions
A function is matched below against an interval where it is supposed to be increasing. Which of the following pairs is incorrectly matched?
Interval | Function |
(-∞, ∞) | x3 – 3x2 + 3x + 3 |
Interval | Function |
[2, ∞) | 2x3 – 3x2 – 12x + 6 |
Interval | Function |
(-∞, 1/3] | 3x2 – 2x + 1 |
Interval | Function |
(- ∞, -4] | x3 + 6x2 + 6 |
C.
Interval | Function |
(-∞, 1/3] | 3x2 – 2x + 1 |
Clearly function f(x) = 3x2 – 2x + 1 is increasing when
f′(x) = 6x – 2 ≥ 0 ⇒ x∈[1/3, ∞)
Sponsor Area
Determine whether each of the following relations are reflexive, symmetric and transitive :
(i) Relation R in the set A = {1, 2, 3,....., 13, 14} defined as
R = {(x, y) : 3 x – y = 0}
(ii) Relation R in the set N of natural numbers defined as R = {(x, y) : y = x + 5 and x < 4} (iii) Relation R in the set A = {1, 2, 3, 4, 5, 6} as R = {(x,y) : y is divisible by x} (iv) Relation R in the set Z of all integers defined as R = {(x,y) : x – y is an integer}
(v) Relation R in the set A of human beings in a town at a particular time given by
(a) R = {(x, y) : x and y work at the same place}
(b) R = {(x,y) : x and y live in the same locality}
(c) R = {(x, y) : x is exactly 7 cm taller than y}
(d) R = {(x, y) : x is wife of y}
(e) R = {(x,y) : x is father of y}
Sponsor Area
Sponsor Area