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x-2-x-3-x-1-2-0-




Question Number 111623 by weltr last updated on 04/Sep/20
(x−2)(x+3)(x−1)^2  ≥ 0
$$\left({x}−\mathrm{2}\right)\left({x}+\mathrm{3}\right)\left({x}−\mathrm{1}\right)^{\mathrm{2}} \:\geqslant\:\mathrm{0} \\ $$
Commented by ZiYangLee last updated on 04/Sep/20
x≤−3 ∪ x≥2?
$${x}\leqslant−\mathrm{3}\:\cup\:{x}\geqslant\mathrm{2}? \\ $$
Commented by weltr last updated on 04/Sep/20
the answer must be   (−∞, −3] ∪ {1} ∪ [2, +∞)
$${the}\:{answer}\:{must}\:{be}\: \\ $$$$\left(−\infty,\:−\mathrm{3}\right]\:\cup\:\left\{\mathrm{1}\right\}\:\cup\:\left[\mathrm{2},\:+\infty\right) \\ $$
Answered by Her_Majesty last updated on 04/Sep/20
(x−1)^2 ≥0∀x∈R but (x−1)^2 =0; x=1  (x−2)(x+3)≥0  ⇒ x≤−3 ∨ x≥2 ∨x=1
$$\left({x}−\mathrm{1}\right)^{\mathrm{2}} \geqslant\mathrm{0}\forall{x}\in\mathbb{R}\:{but}\:\left({x}−\mathrm{1}\right)^{\mathrm{2}} =\mathrm{0};\:{x}=\mathrm{1} \\ $$$$\left({x}−\mathrm{2}\right)\left({x}+\mathrm{3}\right)\geqslant\mathrm{0} \\ $$$$\Rightarrow\:{x}\leqslant−\mathrm{3}\:\vee\:{x}\geqslant\mathrm{2}\:\vee{x}=\mathrm{1} \\ $$

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