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Find-the-domain-and-range-of-relation-a-R-x-y-y-x-2-6-b-R-x-y-x-2-y-2-1-




Question Number 75456 by peter frank last updated on 11/Dec/19
Find the domain and   range of relation  (a)R={(x,y):y=(√(x^2 −6)) }  (b)R={(x,y):x^2 −y^2 =1 }
$${Find}\:{the}\:{domain}\:{and}\: \\ $$$${range}\:{of}\:{relation} \\ $$$$\left({a}\right){R}=\left\{\left({x},{y}\right):{y}=\sqrt{{x}^{\mathrm{2}} −\mathrm{6}}\:\right\} \\ $$$$\left({b}\right){R}=\left\{\left({x},{y}\right):{x}^{\mathrm{2}} −{y}^{\mathrm{2}} =\mathrm{1}\:\right\} \\ $$
Answered by Kunal12588 last updated on 11/Dec/19
(a) x∈(−∞,−(√6)]∪[(√6),∞)  y∈[0,∞) or R_+   (b) x∈(−∞,−1]∪[1,∞)  y∈(−∞,∞) or R
$$\left({a}\right)\:{x}\in\left(−\infty,−\sqrt{\mathrm{6}}\right]\cup\left[\sqrt{\mathrm{6}},\infty\right) \\ $$$${y}\in\left[\mathrm{0},\infty\right)\:{or}\:\mathbb{R}_{+} \\ $$$$\left({b}\right)\:{x}\in\left(−\infty,−\mathrm{1}\right]\cup\left[\mathrm{1},\infty\right) \\ $$$${y}\in\left(−\infty,\infty\right)\:{or}\:\mathbb{R} \\ $$
Answered by vishalbhardwaj last updated on 11/Dec/19
(a) y^2  = x^2 −6  ⇒ x = ± (√(y^2 +6))  ⇒ x ≥ (√6), ∀ y∈ R  ⇒ x∈ [(√(6,)) ∞)  and y∈ [0, ∞)
$$\left(\mathrm{a}\right)\:\mathrm{y}^{\mathrm{2}} \:=\:\mathrm{x}^{\mathrm{2}} −\mathrm{6} \\ $$$$\Rightarrow\:\mathrm{x}\:=\:\pm\:\sqrt{\mathrm{y}^{\mathrm{2}} +\mathrm{6}} \\ $$$$\Rightarrow\:\mathrm{x}\:\geqslant\:\sqrt{\mathrm{6}},\:\forall\:\mathrm{y}\in\:\mathrm{R} \\ $$$$\Rightarrow\:\mathrm{x}\in\:\left[\sqrt{\mathrm{6},}\:\infty\right) \\ $$$$\mathrm{and}\:\mathrm{y}\in\:\left[\mathrm{0},\:\infty\right) \\ $$

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