อ้างอิง:
ข้อความเดิมเขียนโดยคุณ Siren-Of-Step
I have just studied relations : Domain and Range Mr. Metree Sritongtae
Find Domain and Range
2. $r=\left\{\,\right. (x,y) \in R \times R \left|\,\right. \left|\,\right. x\left|\,\right. + \left|\,\right. y\left|\,\right. = 1 \left.\,\right\} $
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$\left|\,\right. a \left|\,\right. \geqslant 0$
$\left|\,\right. y\left|\,\right. = 1-\left|\,\right. x\left|\,\right. $
$1-\left|\,\right. x\left|\,\right.
\left|\,\right. x\left|\,\right. \geqslant 0$
$x = [-1,1]$
$y = [-1,1]$
$D_r = R_r$