

InterviewSolution
Saved Bookmarks
1. |
Let S be the set of all points in a plane and R be a relation on S defines as `R={(P,Q):` distance between `P and Q` is less than 2 units} Show that R is reflexive and symmetric but not transitive. |
Answer» `R = {(P,Q):` distance between `P` and `Q` is less than `2` units. `R` is reflexive as point `P` will have `0` unit distance with `P` which is less than `2`. So, `(P,P) in R`. Now, Let `(P,Q) in R`. `=>` Distance between `P` and `Q` is less than `2` units. `=>` Distance between `Q` and `P` is less than `2` units. `:. (Q,P) in R`. `:. R` is symmetric. Now, Let `(P,Q) in R and (Q, S) in R` It means distance between `P` and `Q` is less than `2` units and distance between `Q` and `S` is less than `2` units. But it is not neccessary, distance beteen `P` and `S` is less than `2` units. `=> (P,S) notinR`. `:. R` is not transitive. Therefore, `R` is reflexive and symmetric but not transitive. |
|