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Sửa đề A = \(\left(\frac{2x+1}{x\sqrt{x}-1}-\frac{1}{\sqrt{x}-1}\right):\frac{\sqrt{x}+3}{x+\sqrt{x}+1}\)
ĐKXĐ : \(\hept{\begin{cases}x\ge0\\x\ne1\end{cases}}\)
Ta có \(\frac{2x+1}{x\sqrt{x}-1}-\frac{1}{\sqrt{x}-1}=\frac{\left(2x+1\right)\left(\sqrt{x}-1\right)-x\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(x\sqrt{x}-1\right)}\)
\(=\frac{x\sqrt{x}+\sqrt{x}-2x}{\left(x\sqrt{x}-1\right)\left(\sqrt{x}-1\right)}=\frac{\sqrt{x}\left(x+1-2\sqrt{x}\right)}{\left[\left(\sqrt{x}\right)^3-1\right]\left(\sqrt{x}-1\right)}=\frac{\sqrt{x}\left(\sqrt{x}-1\right)^2}{\left(\sqrt{x}-1\right)^2\left(x+\sqrt{x}+1\right)}\)
\(=\frac{\sqrt{x}}{x+\sqrt{x}+1}\)
=> A = \(\frac{\sqrt{x}}{x+\sqrt{x}+1}:\frac{\sqrt{x}+3}{x+\sqrt{x}+1}=\frac{\sqrt{x}\left(x+\sqrt{x}+1\right)}{\left(x+\sqrt{x}+1\right)\left(\sqrt{x}+3\right)}=\frac{\sqrt{x}}{\sqrt{x}+3}\)
a,\(\Delta\)ABC vuông tại A ta có:
AC2=HC.BC (ĐL1)
\(\Rightarrow\)HC= AC2/BC=442/55=35,2 (cm)
\(\Delta\)ABC vuông tại A , đường cao AH ta có:
AH2=BH.HC
\(\Rightarrow\)AH=\(\sqrt{\left(BC-HC\right).HC}\)= \(\sqrt{\left(55-35,2\right).35,2}\)=26,4(cm)
b, sinCAH=\(\frac{35,2}{44}\)\(\approx\)53o
\(\hept{\begin{cases}x\ne0\\x\ne\frac{1\pm\sqrt{3}}{2}\end{cases}}\)
\(\overline{abcd}\left(a\ne0\right)\)
\(\overline{abcd}+a+b+c+d=2023\)
\(\left(=\right)a.1000+b.100+c.10+d+a+b+c+d=2023\)
\(\left(=\right)1001a+101b+11c+2d=2023\)
Có \(2023=2.1001+0.101+1.11+2.5\)
\(\Rightarrow a=2;b=0;c=1;d=5\)
\(\Rightarrow abcd=2015\)
\(P=\sqrt{3-x}+\sqrt{4-x}\)(ĐK: \(x\le3\))
\(\le\sqrt{3-3}+\sqrt{4-3}=1\)
Dấu \(=\)khi \(x=3\).