ĐKXĐ: \(\frac{1}{\sqrt{x}-1}-\frac{1}{\sqrt{x}+1}+1\)
Rút gọn biểu thức :
a) \(A=\frac{x}{x-4}+\frac{1}{\sqrt{x}-2}+\frac{1}{\sqrt{x}+2}\) đkxđ : \(x\ge0;x\ne4\)
b) \(B=\left(\frac{\sqrt{x}-1}{\sqrt{x}+1}-\frac{\sqrt{x}+1}{\sqrt{x}-1}\right)\left(\frac{1}{2\sqrt{x}}-\frac{\sqrt{x}}{2}\right)^2\)
c) \(C=\left(\frac{1}{\sqrt{x}}+\frac{\sqrt{x}}{\sqrt{x+1}}\right)\div\frac{\sqrt{x}}{x+\sqrt{x}}\) đkxđ : x > 0
A=\(\frac{x}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}+\frac{1}{\sqrt{x}-2}+\frac{1}{\sqrt{x}+2}\)
=\(\frac{x+\sqrt{x}+2+\sqrt{x}-2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}=\frac{x+2\sqrt{x}}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}\)
=\(\frac{\sqrt{x}\left(\sqrt{x}+2\right)}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)}=\frac{\sqrt{x}}{\sqrt{x-2}}\)
Vậy A=\(\frac{\sqrt{x}}{\sqrt{x}-2}\)vs x\(\ge0;x\ne4\)
C=\(\left(\frac{1+x}{\sqrt{x}\left(\sqrt{x}+1\right)}\right)\times\frac{\sqrt{x}\left(\sqrt{x}+1\right)}{\sqrt{x}}=\frac{1+x}{\sqrt{x}}\)
Vậy C=\(\frac{1+x}{\sqrt{x}}\)vs x>0
1 Cho bt:A=\((\frac{1}{x+\sqrt{x}}+\frac{\sqrt{x}}{\sqrt{x}+1}):\frac{3}{\sqrt{x}+1}\)
Đkxđ và rút gọn
A = \(\frac{1+x}{x+\sqrt{x}}.\frac{\sqrt{x}+1}{3}\)=\(\frac{1+x}{3\sqrt{x}}\)
ĐKXĐ : x > 0
1 Cho bt:\(\frac{1}{\sqrt{x}+1}-\frac{3}{x\sqrt{x}+1}+\frac{2}{x-\sqrt{x}+1}\)
Đkxđ và rút gọn
ĐKXĐ: \(x\ge0\)
\(\frac{1}{\sqrt{x}+1}-\frac{3}{x\sqrt{x}+1}+\frac{2}{x-\sqrt{x}+1}\)
\(=\frac{1}{\sqrt{x}+1}-\frac{3}{\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)}+\frac{2}{x-\sqrt{x}+1}\)
\(=\frac{x-\sqrt{x}+1-3+2\sqrt{x}+2}{\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)}\)
\(=\frac{x+\sqrt{x}}{\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)}\)
\(=\frac{\sqrt{x}\left(\sqrt{x}+1\right)}{\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)}\)
\(=\frac{\sqrt{x}}{x-\sqrt{x}+1}\)
\(B=\left(\frac{2\sqrt{x}+x}{x\sqrt{x}-1}-\frac{1}{\sqrt{x}-1}\right):\frac{x-1}{x+\sqrt{x}+1}\)
Tìm đkxđ
Rút gọn B
\(ĐKXĐ:\hept{\begin{cases}\sqrt{x}-1\ne0\\x\ge0\end{cases}\Leftrightarrow}\hept{\begin{cases}x\ne1\\x\ge0\end{cases}}\)
\(B=\left(\frac{2\sqrt{x}+x}{x\sqrt{x}-1}-\frac{1}{\sqrt{x}-1}\right):\frac{x-1}{x+\sqrt{x}+1}\)
\(=\left(\frac{2\sqrt{x}+x}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}-\frac{x+\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}\right).\frac{x+\sqrt{x}+1}{x-1}\)
\(=\left(\frac{2\sqrt{x}+x-x-\sqrt{x}-1}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}\right).\frac{x+\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\)
\(=\frac{\sqrt{x}-1}{\left(\sqrt{x}-1\right)}.\frac{1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\)
\(=\frac{1}{x-1}\)
(\(M=\left(\frac{1}{\sqrt{x}-1}-\frac{2\sqrt{x}}{x\sqrt{x}+\sqrt{x}-x-1}\right):\left(\frac{\sqrt{x}}{x+1}+1\right)\)
tìm ĐKXĐ, giải phương trình
Bài 1:
A=\(\left(\frac{1}{\sqrt{x}}+\frac{\sqrt{x}}{\sqrt{x}+1}\right):\frac{\sqrt{x}}{\sqrt{x}\left(\sqrt{x}+1\right)}\)
a, tìm ĐKXĐ
b, rút gọn
Bài 2.
B=\(\left(\frac{3}{x-1}+\frac{1}{\sqrt{x}+1}\right):\frac{1}{\sqrt{x}+1}\)
a, Tìm ĐKXĐ
b, rút gọn
Giúp mình nha mình đang cần gấp.!!!!!!
1 Cho bt:A=\((\frac{1}{x+\sqrt{x}}+\frac{\sqrt{x}}{\sqrt{x+1}}):\frac{3}{\sqrt{x+1}}\)
Đkxđ và rút gọn
Tìm x để \(\frac{1}{\sqrt{x}}.A=1\)
tìm đkxđ và rút gọn
\(\left(\frac{\sqrt{x}}{\sqrt{x+1}}-\frac{1}{x+\sqrt{x}}\right).\frac{1}{\sqrt{x}-1}\)
sửa đề: \(\frac{\sqrt{x}}{\sqrt{x}+1}\)
đkxđ: \(\left\{{}\begin{matrix}\sqrt{x}\ge0\\\sqrt{x}+1\ne0\left(lđ\right)\\x+\sqrt{x}\ne0\\\sqrt{x}-1\ne0\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x\ge0\\\sqrt{x}\left(\sqrt{x}+1\right)\ne0\\x\ne1\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\ge0\\x\ne0\\x\ne1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x>0\\x\ne1\end{matrix}\right.\)
ta có: \(\left(\frac{\sqrt{x}}{\sqrt{x}+1}-\frac{1}{x+\sqrt{x}}\right).\frac{1}{\sqrt{x}-1}\)
=\(\left[\frac{x}{\sqrt{x}\left(\sqrt{x}+1\right)}-\frac{1}{\sqrt{x}\left(\sqrt{x}+1\right)}\right].\frac{1}{\sqrt{x}-1}\)
=\(\frac{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}{\sqrt{x}\left(\sqrt{x}+1\right)}.\frac{1}{\sqrt{x}-1}\) =\(\frac{1}{\sqrt{x}}\)
vậy...
P= \(\frac{x+2}{x\sqrt{x}-1}+\frac{\sqrt{x}+1}{x+\sqrt{x}+1}-\frac{\sqrt{x}-1}{x-1}\)
a) Tìm đkxđ và rút gọn P
b) Tìm x để P=\(\frac{2}{7}\)
c) CHo M=P.\(\frac{x+\sqrt{x}+1}{\sqrt{x}-2}\). Tìm x nguyên để M nguyên
d) So sánh P và \(\frac{1}{3}\)với mọi x tm đkxđ