Question

[Bé con]

Tìm ĐKXĐ : a) \(3-\sqrt{1-16x^2}\)

b)\(\frac{1}{1-\sqrt{x^2-3}}\)

c) \(\sqrt{8x-x^2-15}\)

d) \(\frac{2}{\sqrt{x^2-x+1}}\)

e) \(\frac{1}{\sqrt{x-\sqrt{2x-1}}}\)

g)\(\frac{\sqrt{10-x^2}}{\sqrt{2x+1}}+\sqrt{x^2-8x+14}\)

Answer 1

[Tuyển Trần Thị]

a, dk \(1-16x^2\ge0\Leftrightarrow\left(1-4x\right)\left(1+4x\right)\ge0\)

        \(\Leftrightarrow-\frac{1}{4}\le x\le\frac{1}{4}\)

b tuong tu

c, \(\sqrt{\left(x-3\right)\left(5-x\right)}\ge0\Leftrightarrow\left(x-3\right)\left(5-x\right)\ge0\Leftrightarrow3\le x\le5\)

d.\(\sqrt{x^2-x+1}>0\)

ma \(x^2-x+1=x^2-2.\frac{1}{2}x+\frac{1}{4}+\frac{3}{4}=\left(x-\frac{1}{2}\right)^2+\frac{3}{4}>0\)

suy ra thoa man vs moi x