\(\sqrt{x+x^2}+\sqrt{x-x^2}=x+1\)
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a: \(A=\dfrac{-\left(\sqrt{x}-2\right)}{\sqrt{x}-1}:\dfrac{x-1-x+4}{\left(\sqrt{x}-2\right)\left(\sqrt{x}-1\right)}\)
\(=\dfrac{-\left(\sqrt{x}-2\right)^2}{3}\)
Đề bạn gõ sai, mình có sửa lại r nha
\(a,A=\dfrac{1-\sqrt{x}+1}{\sqrt{x}-1}:\dfrac{x-1-x+4}{\left(\sqrt{x}-2\right)\left(\sqrt{x}-1\right)}=\dfrac{\sqrt{x}}{\sqrt{x}-1}\cdot\dfrac{\left(\sqrt{x}-2\right)\left(\sqrt{x}-1\right)}{3}=\dfrac{\sqrt{x}\left(\sqrt{x}-2\right)}{3}\\ x=5\Leftrightarrow A=\dfrac{\sqrt{5}\left(\sqrt{5}-2\right)}{3}=\dfrac{5-2\sqrt{5}}{3}\\ c,A=-\dfrac{1}{3}\Leftrightarrow\sqrt{x}\left(\sqrt{x}-2\right)=-1\Leftrightarrow x-2\sqrt{x}+1=0\\ \Leftrightarrow\left(\sqrt{x}-1\right)^2=0\Leftrightarrow x=1\left(ktm\right)\Leftrightarrow x\in\varnothing\)
a. \(C=\frac{2\sqrt{x}-9}{x-5\sqrt{x}+6}-\frac{\sqrt{x}+3}{\sqrt{x}-2}-\frac{2\sqrt{x}+1}{3-\sqrt{x}}\)
\(=\frac{2\sqrt{x}-9}{\left(\sqrt{x}-3\right)\left(\sqrt{x}-2\right)}-\frac{\sqrt{x}+3}{\sqrt{x}-2}+\frac{2\sqrt{x}+1}{\sqrt{x}-3}\)
\(=\frac{2\sqrt{x}-9-\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)+\left(2\sqrt{x}+1\right)\left(\sqrt{x}-2\right)}{\left(\sqrt{x}-3\right)\left(\sqrt{x}-2\right)}\)
\(=\frac{2\sqrt{x}-9-x+9+2x-4\sqrt{x}+\sqrt{x}-2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}-3\right)}\)
\(=\frac{x-\sqrt{x}-2}{\left(\sqrt{x}-3\right)\left(\sqrt{x}-2\right)}=\frac{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}{\left(\sqrt{x}-2\right)\left(\sqrt{x}-3\right)}=\frac{\sqrt{x}+1}{\sqrt{x}-3}\)
b. C=\(\frac{\sqrt{x}+1}{\sqrt{x}-3}=1+\frac{4}{\sqrt{x}-3}\)
C nguyên \(\Leftrightarrow\sqrt{x}-3\inƯ\left(4\right)\Rightarrow\sqrt{x}-3\in\left\{-4;-2;-1;1;2;4\right\}\)
\(\Rightarrow\sqrt{x}\in\left\{1;2;4;5;7\right\}\Rightarrow x\in\left\{1;4;16;25;49\right\}\)
Vậy \(x\in\left\{1;4;16;25;49\right\}\)thì C nguyên
\(M=\dfrac{3}{2}\cdot4\sqrt{2x}-\dfrac{1}{3}\cdot3\sqrt{2x}+\dfrac{2}{5}\cdot5\sqrt{2x}-4\sqrt{2x}=6\sqrt{2x}-\sqrt{2x}+2\sqrt{2x}-4\sqrt{2x}=3\sqrt{2x}\)
a) ĐKXĐ: x\(\ne\) 0;4
Ta có: Q= \(\left(\frac{4\sqrt{x}}{2+\sqrt{x}}+\frac{8x}{\left(2-\sqrt{x}\right)\left(2+\sqrt{x}\right)}\right):\left(\frac{\sqrt{x}-1}{\sqrt{x}\left(\sqrt{x}-2\right)}-\frac{2}{\sqrt{x}}\right)\)
= \(\frac{4\sqrt{x}\cdot\left(2-\sqrt{x}\right)+8x}{\left(2-\sqrt{x}\right)\left(2+\sqrt{x}\right)}:\frac{\sqrt{x}-1-2\cdot\left(\sqrt{x}-2\right)}{\sqrt{x}\left(\sqrt{x}-2\right)}\)
=\(\frac{8\sqrt{x}+4x}{\left(2-\sqrt{x}\right)\left(2+\sqrt{x}\right)}\cdot\frac{\sqrt{x}\left(\sqrt{x}-2\right)}{3-\sqrt{x}}\)= \(\frac{4\sqrt{x}\cdot\left(2+\sqrt{x}\right)}{2+\sqrt{x}}\cdot\frac{-\sqrt{x}}{3-\sqrt{x}}\)=\(\frac{-4}{3-\sqrt{x}}\)=\(\frac{4}{\sqrt{x}-3}\)
b) Q=-1 => \(\frac{4}{\sqrt{x}-3}=-1\)
<=> \(4=3-\sqrt{x}\)
<=> \(\sqrt{x}=-1\) (vô lí)
Vậy ko tìm được x.
\(\Rightarrow C=1+\left[\frac{\left(2\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}{\left(1-\sqrt{x}\right)\left(\sqrt{x}+1\right)}-\frac{2x\sqrt{x}-\sqrt{x}+x}{\left(1-\sqrt{x}\right)\left(1+\sqrt{x}+x\right)}\right].\frac{x-\sqrt{x}}{2\sqrt{x}-1}\)
\(=1+\left[\frac{\left(2\sqrt{x}-1\right)\left(1+\sqrt{x}+x\right)-\left(2x\sqrt{x}-\sqrt{x}+x\right)}{\left(1-\sqrt{x}\right)\left(1+\sqrt{x}+x\right)}\right].\frac{x-\sqrt{x}}{2\sqrt{x}-1}\)
\(=1+\left[\frac{2\sqrt{x}+2x+2x\sqrt{x}-1-\sqrt{x}-x-2x\sqrt{x}+\sqrt{x}-x}{\left(1-\sqrt{x}\right)\left(1+\sqrt{x}+x\right)}\right].\frac{\sqrt{x}\left(\sqrt{x}-1\right)}{2\sqrt{x}-1}\)
\(=1+\left[\frac{2\sqrt{x}-1}{\left(1-\sqrt{x}\right)\left(1+\sqrt{x}+x\right)}\right].-\frac{\sqrt{x}\left(1-\sqrt{x}\right)}{2\sqrt{x}-1}\)
\(=1-\frac{\sqrt{x}}{1+\sqrt{x}+x}\) \(=\frac{1+\sqrt{x}+x-\sqrt{x}}{1+\sqrt{x}+x}=\frac{1+x}{1+\sqrt{x}+x}\)
- Đề đầy đủ rồi nhé các bạn. KO CÓ cộng thêm căn xy bên phải đâu tại tớ nhìn bị thiếu á -.-
Đề bài ko chính xác, nếu x bất kì thì tồn tại vô số x để P nguyên
Nếu \(x\) nguyên thì mới có hữu hạn giá trị x
ĐKXĐ : \(0\le x\le1\)
Bình phương 2 vế được : \(2x+2\sqrt{x^2-x^4}=x^2+2x+1\) ( do x \(\ge0\Rightarrow x+1>0\) )
\(\Leftrightarrow2\sqrt{x^2-x^4}=x^2+1\Leftrightarrow4\left(x^2-x^4\right)=x^4+2x^2+1\)
\(\Leftrightarrow5x^4-2x^2+1=0\) \(\Leftrightarrow PTVN\)