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1.Relation and Function
normal
If $f:\left\{ {1,2,3,4} \right\} \to \left\{ {1,2,3,4} \right\}$ and $y=f(x)$ be a function such that $\left| {f\left( \alpha \right) - \alpha } \right| \leqslant 1$,for $\alpha \in \left\{ {1,2,3,4} \right\}$ then total number of such functions are
A
$81$
B
$36$
C
$54$
D
none of these
Solution
Total cases $= 2\times 3 \times 3 \times 2 = 36$
Standard 12
Mathematics