Page 25 - Mathematics Class - XI

Viva-Voce

1. What is meant by a term function?
Ans. A function f from a set A to a set B is a specific type of relation for which every element x of set A has one
and only one image y in set B.
i.e., f : A → B, where f(x) = y.
2. Is the statement “Every function is a relation but not conversely” true or not?
Ans. True

3. What is meant by a constant function?
Ans. A constant function is a linear function for which the range does not change no matter which member of
the domain is used.
4. Name different types of functions.
Ans. Identity function, constant function, polynomial function, rational function, modulus function, signum
function and greatest integer function.
5. If f : A → B, what is the domain and co-domain of function f ?
Ans. If f : A → B, the set A is the domain of f and the set B is the co-domain of f.

MCQs

1. The range of f (x) = 1
−
12cos x

a) 1 3 1 , b) 1, 1 c) 1 1 d) , 1 1 ,

,

3
3
3
x 2 x 1
2
2. The domain of function f defined by f (x) =
x
2
x 6
a) R – {3, –2} b) R – {–3, 2} c) R – [3, –2] d) R – (3, –2)
3. The domain and range of f defined by f (x) = 2 – | x – 5|
a) domain = R , range = ( –∞, 1] b) domain = R, range = ( –∞, 2]
+
c) domain = R, range = ( –∞, 2) d) domain = R , range = ( –∞, 2]
+
2
4. The domain of a − x (a > 0)
2
a) (–a, a) b) [–a, a] c) [0, a] d) [–a, 0]
x 2 x2 1
5. The domain of the function f (x)
x 2 x8 12
a) Set of all real number b) Set of all real number except 2 and 6
c) Set of all real number except 8 d) Set of all real number except 12
1
Answers: 1. b) 1, 3 2. a) R – {3, –2} 3. b) domain = R, range = ( –∞, 2]

4. b) [–a, a] 5. b) Set of all real number except 2 and 6
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