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Let `R`be a relation defined on the set of naturalnumbers `N`as `R={(x , y): x , y in N , 2x+y=41}`Find the domain and range of `R`. Also, verify whether `R`is (i) reflexive, (ii) symmetric (iii) transitive. |
Answer» `2x+y = 41` `=>x = (41-y)/2` `:. y in {1,3,5,7....39}`, which is range of `R`. `:. x in {1,2,3,4...19,10}`, which is domain of `R`. Now,`R = {(x,y): x,y in N and 2x+y = 41}` Now, for `(a,a)`, `2a+a = 41, => a = 41/3 => a !in N` `:. (a,a) !in R` `:. R` is not reflexive. `(a,b) in R`. It means `2a+b = 41`. But, it is not neccessaty that `2b+a = 41`.`:. (b,a) notin R`. `:. R` is not symmetric. If `(a,b) in R`, Then, `2a+b = 41`. If `(b,c) in R`, Then, `2b+c = 41` Then, `2a+b+2b+c = 82` `=>2a+3b+c =82` For `2a+c = 41`, `3b = 41 or b = 41/3 `, which is not true as `b in N`. `:. (a,c) notin R`. `:. R` is not transitive. |
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