Question

A relation n$\varphi$ from C to R is defined by $x\varphi y\iff |x|=y.$ Which one is correct ?

• A. $(2+3i)\varphi 13$
• B. $3\varphi (-3)$
• C. $(1+i)\varphi 2$
• D. $i\varphi 1.$

Answer 1

The correct option is D

$i\varphi 1.$

We have $|i|=\sqrt{1^2+0^2}=1$
Thus, $i\varphi 1$ satisfies $x\varphi y\iff |x|=y.$