giải PT
\(\sqrt{x-\frac{1}{x}}-\sqrt{1-\frac{1}{x}}=\frac{x-1}{x}\)
Giải pt: \(\frac{1}{\sqrt{x+3}+\sqrt{x+2}}+\frac{1}{\sqrt{x+2}+\sqrt{x+1}}+\frac{1}{\sqrt{x+1}+\sqrt{x}}=1\)
Giải pt \(\frac{1}{\sqrt{x-1}+\sqrt{x-2}}+\frac{1}{\sqrt{x-2}+\sqrt{x-3}}+...+\frac{1}{\sqrt{x-9}+\sqrt{x-10}}=1\)
\(\sqrt{1+\frac{1}{x+1}}+\frac{1}{\sqrt{x+1}}=\sqrt{x}+\frac{1}{\sqrt{x}}\)
Giải pt
Giải pt \(\frac{1}{\sqrt{x+3}+\sqrt{x+2}}+\frac{1}{\sqrt{x+2}+\sqrt{x+1}}+\frac{1}{\sqrt{x+1}+\sqrt{x}}=1\)
GIÚP MK ĐI!!!!!!!!
olm còn lỗi nên ko trình bày bth đc, bn tự viết lại nhá :))
\(\frac{1}{\sqrt{x+3}+\sqrt{x+2}}=\frac{\sqrt{x+3}-\sqrt{x+2}}{\left(\sqrt{x+3}+\sqrt{x+2}\right)\left(\sqrt{x+3}-\sqrt{x+2}\right)}\)
\(\frac{1}{\sqrt{x+2}+\sqrt{x+1}}=\frac{\sqrt{x+2}-\sqrt{x+1}}{\left(\sqrt{x+2}+\sqrt{x+1}\right)\left(\sqrt{x+2}-\sqrt{x+1}\right)}\)
\(\frac{1}{\sqrt{x+1}+\sqrt{x}}=\frac{\sqrt{x+1}-\sqrt{x}}{\left(\sqrt{x+1}+\sqrt{x}\right)\left(\sqrt{x+1}-\sqrt{x}\right)}\)
\(VT=\sqrt{x+3}-\sqrt{x+2}+\sqrt{x+2}-\sqrt{x+1}+\sqrt{x+1}-\sqrt{x}\)
\(VT=\sqrt{x+3}-\sqrt{x}=1\)
Dễ r -,-
1.Giải pt sau:(\(\sqrt{2}\) +2)(x\(\sqrt{2}\) -1)=2x\(\sqrt{2}\) -\(\sqrt{2}\)
2.Cho pt: 2(a-1).x-a(x-1)=2a+3
3.Giải pt sau:
a) \(\frac{2}{x+\frac{\text{1}}{\text{1}+\frac{x+\text{1}}{x-2}}}=\frac{6}{3x-\text{1}}\)
b) \(\frac{\frac{x+\text{1}}{x-\text{1}}-\frac{x-\text{1}}{x+\text{1}}}{\text{1}+\frac{x+\text{1}}{x-\text{1}}}=\frac{x-\text{1}}{2\left(x+\text{1}\right)}\)
1) Nhìn cái pt hết ham, nhưng bấm nghiệm đẹp v~`~
\(\left(\sqrt{2}+2\right)\left(x\sqrt{2}-1\right)=2x\sqrt{2}-\sqrt{2}\)
\(\Leftrightarrow\left(\sqrt{2}+2\right)\left(x\sqrt{2}-1\right)-2x\sqrt{2}+\sqrt{2}=0\)
\(\Leftrightarrow2x-\sqrt{2}+2x\sqrt{2}-2-2x\sqrt{2}+\sqrt{2}=0\)
\(\Leftrightarrow2x-2=0\Leftrightarrow2x=2\Rightarrow x=1\)
Mấy bài kia sao cái phương trình dài thê,s giải sao nổi
Giải pt: \(x+\sqrt[3]{x^3-x^2}+\sqrt[3]{x^3-x}=\sqrt[3]{x^2+x+\frac{1}{3}}+\sqrt[3]{x^2+\frac{1}{3}}+\sqrt[3]{x+\frac{1}{3}}\)
Giải pt: x=\(\sqrt{x-\frac{1}{x}}+\sqrt{1-\frac{1}{x}}\)
Đk \(x\ge1\)
Áp dụng bđt cosi có
\(\sqrt{x-\frac{1}{x}}=\sqrt{1\left(x-\frac{1}{x}\right)}\le\frac{1+x-\frac{1}{x}}{2}\)
\(\sqrt{1-\frac{1}{x}}=\sqrt{\frac{1}{x}\left(x-1\right)}\le\frac{\frac{1}{x}+x-1}{2}\)
\(\Rightarrow VT\le VP\)
Dấu = xay ra khi.........\(x=\frac{1+\sqrt{5}}{2}\)(do \(x\ge1\))
*ĐK* : \(\hept{\begin{cases}x\ne0\\x-\frac{1}{2}\ge0\\1-\frac{1}{x}\ge0\end{cases}\Leftrightarrow x\ge1}\)(1)
\(x\ge0\)( điều kiện cần )
\(\left(1\right)\Leftrightarrow x\sqrt{x}=\sqrt{x^2-1}+\sqrt{x-1}\)
\(\Leftrightarrow x\sqrt{x}=\sqrt{x-1}\left(\sqrt{x+1}+1\right)\)
\(\Leftrightarrow x\sqrt{x}=\sqrt{x-1}.\frac{\left(x+1\right)-1}{\sqrt{x+1}-1}\)
\(\Leftrightarrow\sqrt{x}.\left(\sqrt{x+1}-1\right)=\sqrt{x-1}\)( vì \(x\ge1>0\))
\(\Leftrightarrow x\left(x+2-2\sqrt{x+1}\right)=x-1\)( vì \(x\ge1\)nên \(\sqrt{x+1}-1>0\))
\(\Leftrightarrow x^2+x+1-2x.\sqrt{x+1}=0\)
\(\Leftrightarrow x^2-2x\sqrt{x+1}+\left(x+1\right)=0\)
\(\Leftrightarrow x-\sqrt{x+1}=0\Leftrightarrow x=\sqrt{x+1}\Leftrightarrow x^2=x+1\)
\(\Leftrightarrow x^2-x-x=0\Leftrightarrow x=\frac{1+\sqrt{5}}{2}\)hoặc \(x=\frac{1-\sqrt{5}}{2}\)
\(\Leftrightarrow x=\frac{1+\sqrt{5}}{2}\)( vì đk \(x\ge1\))
Vậy nghiệm của PT trên là \(x=\frac{1+\sqrt{5}}{2}\)
Giải pt: \(\frac{\sqrt{x+1}}{\sqrt{x+1}-\sqrt{3-x}}=x-\frac{1}{2}\)
giải bất pt sau:
\(\frac{\sqrt{x^{2^{ }}-x-2}}{\sqrt{x-1}}+\sqrt{x-1}< \frac{2x+1}{\sqrt{x-1}}\)
Dk 1<x<2
√x^2 -x -2<x+2
5x+6>0
X > -6/5
Bpt vô nghiệm