FunctionHard
Question
Consider two sets $A = \{ x \in z:|(|x - 3| - 3)| \leq 1\}$ and $B = \left\{ x \in \mathbb{R} - \{ 1,2\}:\frac{(x - 2)(x - 4)}{x - 1}\log_{e}(|x - 2|) = 0 \right\}$.
Then the number of onto functions $f:A \rightarrow B$ is equal to :
Options
A.62
B.79
C.32
D.81
Solution
A : $||x - 3| - 3| \leq 1$
$${\Rightarrow - 1 \leq |x - 3| - 3 \leq 1 }{2 \leq |x - 3| \leq 4 }$$$2 \leq (x - 3) \leq 4$ or $- 4 \leq (x - 3) \leq - 2$
$5 \leq x \leq 7\ $ or $- 1 \leq x \leq 1$
$$A = \{ - 1,0,1,5,6,7\} $$$B \Rightarrow x = 4,|x - 2| = 1 \Rightarrow x = 3$ or 1 (reject) +
$$B = \{ 3,4\} $$Number of onto functions from A to $B = 2^{6} - 2 = 62$
Create a free account to view solution
View Solution FreeMore Function Questions
If f : R → R , f(x) = 2x ; g : R → R, g(x) = x + 1, then (f .g) (2) equals -...If f(x) = log x, then f (x/y) equals-...If f (x) = log and g(x) =, then f[g(x)] is equal to-...f(x) = values of ′a′ for which f(x) is injective is-...Let f (x) = , x ∈ R. Then range of f (x), where [.] denotes greatest integer function, is :...