Maths Olympiad Prep

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Algebra Difficulty 4.7 AIME Find the answer

18, Find the domain of the independent variable xx for the following functions:
(1) y=1x2y=\frac{1}{\sqrt{|x|-2}};
(2) y=1lgx2y=\frac{1}{\lg \sqrt{x-2}};
(3) y=13x2y=\frac{1}{3-\sqrt{x-2}};
(4) y=1lgx2y=\frac{1}{| \lg | x-2 |};
(5) y=lg(x1)2xy=\frac{\lg (x-1)}{2-\sqrt{x}};
(6) y=2x÷1x+1y=\sqrt{2-x} \div \frac{1}{\sqrt{x+1}}.

A number or a short expression. Fractions can be typed as 3/2, and spacing doesn't matter.

Solution

(Ans: (1) x>2x>2 and x2x2 and x3x \neq 3, (3) x2x \geqslant 2 and x11x \neq 11, (4) x1,2,3x \neq 1,2,3, (5) x>1x>1 and x4x \neq 4, (6) 1<x2-1<x \leqslant 2 )

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Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic and difficulty added by this site.