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1.Relation and Function
hard
ત્રણ, $\{a, b, c \}$ પરનો સંબંધ $R =\{( a , b ),( b , c )\}$ સંમિત અને પરંપરિત બને તે માટે તેમાં ન્યુનતમ ઘટકો ઉમેરવા પડે.
A
$4$
B
$7$
C
$5$
D
$3$
(JEE MAIN-2023)
Solution
For Symmetric $(a, b),(b, c) \in R$
$\Rightarrow(b, a),(c, b) \in R$
For Transitive $(a, b),(b, c) \in R$
$\Rightarrow(a, c) \in R$
Now
$1.$ Symmetric
$\therefore(a, c) \in R \Rightarrow(c, a) \in R$
$2.$ Transitive
$\therefore(a, b),(b, a) \in R$
$\Rightarrow(a, a) \in R \&(b, c),(c, b) \in R$
$\Rightarrow(b, b) \&(c, c) \in R$
$\therefore$ Elements to be added
$\left\{\begin{array}{r}(b, a),(c, b),(a, c),(c, a) \\,(a, a),(b, b),(c, c)\end{array}\right\}$
Number of elements to be added $=7$
Standard 12
Mathematics