the domain of this quadratic relation in my math book is D= {X E R| 2 <_ x <_ 9} and the range is R = {y E R| 1 <_ y <_ 5} but I don't get what the E R means can someone please tell me.

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- Aug 21st 2008, 11:11 AMOryonNeed help Grade 11 math
the domain of this quadratic relation in my math book is D= {X E R| 2 <_ x <_ 9} and the range is R = {y E R| 1 <_ y <_ 5} but I don't get what the E R means can someone please tell me.

- Aug 21st 2008, 11:19 AMo_O
$\displaystyle D = \{x \in \mathbb{R} : 2 \leq x \leq 9\}$

Translation: The domain consists of all x in the set of real numbers such that x is greater than equal to 2 and less than or equal to 9.

$\displaystyle \in$ means 'belongs to'. $\displaystyle \mathbb{R}$ refers to the set of all real numbers.