JEE Mains · Maths · STD 12 - 1. relation and function
The number of strictly increasing functions f from the set {1, 2, 3, 4, 5, 6} to the set {1, 2, 3,...,9} such that \( f(i)\ne i \) for \( 1\le i\le6, \) is equal to:
- A 21
- B 27
- C 22
- D 28
Answer & Solution
Correct Answer
(D) 28
Step-by-step Solution
Detailed explanation
\(f(i) \ \neq i\), \( f(x) \) is strictly increasing function f: \( A\rightarrow B \), where A={1,2,3...6}, B \(\{1,2,3, \ldots . .9\}\), then number of function \(f : A \rightarrow B\) is equal to \(f(i) \ \neq i\) Case-i: \( f(1)=2\Rightarrow^{7}C_{5}=21 \) Case-ii:…
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