00:01
Hi, here we have to show various relations are equivalence relations.
00:03
So first is x is related to y if and only if x minus y is even, where x and y are integers.
00:14
So x minus y even implies y minus x is also even.
00:21
Similarly, x minus x is 0 which is also even.
00:28
So this implies if x is related to y, y is also related to x and also x is related to x, which implies x is symmetric as well as reflexive.
00:45
Now if x is related to y and y is related to z, this implies x minus y and y minus z both are even.
01:05
X minus z which can be written as x minus y minus of y minus z is again even because even minus even is even is even this implies x is related to z therefore r is transitive so all these implies together r is an equivalence relation now we have to find equivalence class of 7.
01:46
So we know that 7 minus x is even.
01:50
It implies x is odd which implies equivalence class of 7 is odd integers similarly.
02:08
So the other equivalence class will be set of even integers.
02:14
So therefore number of equivalence classes is equal to 2.
02:25
That is set of quad integers and set of even integer.
02:29
X is related to y if and only if x's intersection with 1 ,3 ,5 is equal to y intersection with 1, 3, 5 where x and y are subsets of 1, 2, 3, 4 .5...