Page 9 - E booklet prep 3 bader 2025 b_Neat

2-Relations

The relation is repersent by the symbol " R " where :

R ? cartesian product

Note:

? in any example the relation become after the word " means "
? the relation from a set to itself write as R ? ?? × ??

Example1:

If X = { -1 , 1 , 2 } , Y = { 2 , 4 , 6 , 8 } and R is a relation from X to Y where aRb
means : " b = 2a + 4 " for each a ? X , b ? Y write and represent R in an
arrow diagram
R = { { -1 , 2 ) , ( 2 , 6 ) , ( 2 , 8 ) }

Example 2:

If X = { -2 , -1 , 0 , 1 , 2 } , and R is a relation from X to X where aRb means :
" the number a is the additive inverse of the number b " for each a ? X , b ?
X write R and represent it by an arrow diagram
R = { { -2 , 2 ) , ( -1 , 1 ) , ( 0 , 0 ) , ( 1 , -1 ) , ( 2 , -2 ) }

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