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Question
A relation ϕ from C to R is defined by x ϕ y ⇔ | x | = y. Which one is correct?
Options
(2 + 3 i) ϕ 13
3 ϕ (−3)
(1 + i) ϕ 2
i ϕ 1
Solution
i ϕ 1
∵ `| 2 +3 | = sqrt13 ≠ 13`
|3| ≠ -3
`| 1+ i| = sqrt2 ≠2`
and | i |=1
So, (i, 1) ∈ ϕ
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