Test Index
NCERT Class XI Mathematics - Relations and Functions - Solutions
© examsnet.com
Question : 25 of 36
Marks:
+1,
-0
The relation f is defined by f (x) = The relation g is defined by g (x) = Show that f is a function and g is not a function.
Solution:
(i) Given relation is f (x) = Here f (x) = for all x ∈ [0, 3] ⇒ f(3) = = 9 and f (x) = 3x for all x ∈ [3, 10] ⇒ f(3) = 3 × 3 = 9. It shows that f (x) takes unique value at each point in its domain [0, 10]. Hence, f (x) is a function. (ii) Given relation is g (x) = Here, g(x) = ∀ x ∈ [0, 2] ⇒ g(2) = = 4 and g(x) = 3x ∀ x ∈ [2, 10] ⇒ g(2) = 3 × 2 = 6 It shows that g(x) does not take unique value at point 2. Hence, g(x) is not a function.
© examsnet.com
Go to Question: