Giải nhanh giúp em với ạ

Question

Giải nhanh giúp em với ạ
giai-nhanh-giup-em-voi-a

in progress 0
Maris 4 years 2020-10-29T20:29:40+00:00 2 Answers 68 views 0

Answers ( )

  1. Ladonna
    0
    2020-10-29T20:31:03+00:00
    Reply

    `a)`

    \(\left\{ \begin{array}{l}1 + \sqrt{1 – x} \ne 0\\1 – \sqrt{1 – x} \ne 0\\1 – x ≥ 0\end{array} \right.\) 

    `<=>` \(\left\{ \begin{array}{l}\sqrt{1 – x} \ne -1 (l)\\\sqrt{1 – x} \ne 1\\x ≤ 1\end{array} \right.\) 

    `<=>` \(\left\{ \begin{array}{l}x \ne 0\\x ≤ 1\end{array} \right.\) 

    `=> D = (-∞; 1] \\ {0}`

    `b)`

    \(\left\{ \begin{array}{l}x ≥ 0\\x + 2\sqrt{x} + 1 \ne 0\\x – 1 \ne 0\end{array} \right.\)  

    `<=>` \(\left\{ \begin{array}{l}x ≥ 0\\(\sqrt{x} + 1)² \ne 0 (ld)\\x \ne 1\end{array} \right.\) 

    `=> D =[0; +∞) \\ {1}` 

  2. Nem
    0
    2020-10-29T20:31:05+00:00
    Reply

    a) $y = \dfrac{1}{1 + \sqrt{1 – x}} + \dfrac{1}{1 – \sqrt{1 – x}}$

    $y$ xác định $\Leftrightarrow \begin{cases}1 – x\geq 0\\\sqrt{1 – x} \ne 1\end{cases}\Leftrightarrow \begin{cases}x \leq 1 \\x \ne 0\end{cases}$

    $\Rightarrow TXD: D =(-\infty;1]\backslash\left\{0\right\}$

    Hoặc $D = (-\infty;0)\cup(0;1]$

    b) $y = \dfrac{\sqrt x – 2}{x + 2\sqrt x + 1} – \dfrac{\sqrt x + 2}{x – 1}$

    $y$ xác định $\Leftrightarrow \begin{cases}x \geq 0\\x – 1 \ne 0\end{cases} \Leftrightarrow \begin{cases}x \geq 0\\x \ne 1\end{cases}$

    $\Rightarrow TXD: D = [0;+\infty)\backslash\left\{1\right\}$

    Hoặc $D = [0;1)\cup (1;+\infty)$

Leave an answer

Browse

Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )