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b: \(\sqrt{9-4\sqrt{2}}=2\sqrt{2}-1\)
c: \(\sqrt{9+4\sqrt{2}}=2\sqrt{2}+1\)
10: Ta có: \(\left(\dfrac{x-4}{x-2\sqrt{x}}+\dfrac{3}{\sqrt{x}-2}\right):\left(\dfrac{\sqrt{x}+2}{\sqrt{x}}-\dfrac{\sqrt{x}}{\sqrt{x}-2}\right)\)
\(=\dfrac{x+3\sqrt{x}-4}{\sqrt{x}\left(\sqrt{x}-2\right)}\cdot\dfrac{\sqrt{x}\left(\sqrt{x}-2\right)}{x-4-x}\)
\(=\dfrac{-x-3\sqrt{x}+4}{4}\)
3: P=A*B
\(=\dfrac{2\sqrt{x}+5}{\sqrt{x}-1}\cdot\dfrac{\sqrt{x}-1}{\sqrt{x}+3}\)
\(=\dfrac{2\sqrt{x}+5}{\sqrt{x}+3}\)
\(P-1=\dfrac{2\sqrt{x}+5-\sqrt{x}-3}{\sqrt{x}+3}=\dfrac{\sqrt{x}+2}{\sqrt{x}+3}>0\)
=>P>1
=>\(P>\sqrt{P}\)
1: góc AHC+góc AKC=180độ
=>AHCK nội tiếp
2: góc AHK=góc ACK=góc ABC
3: AH^2=AI*AK
=>AH^2=2*AM*2NA
mà AH=AM+AN
nên (AM-AN)^2=0
=>AM=AN
=>2AM=2AN
=>AP=AK
=>A nằm chính giữa cung BC
=>A,O,H thẳng hàng
a: Xét tứ giác OBAC có
\(\widehat{OBA}+\widehat{OCA}=180^0\)
Do đó: OBAC là tứ giác nội tiếp
a: \(x=\sqrt{27+10\sqrt{2}}-\sqrt{18+8\sqrt{2}}+8\)
\(=\sqrt{\left(5+\sqrt{2}\right)^2}-\sqrt{\left(4+\sqrt{2}\right)^2}+8\)
\(=5+\sqrt{2}-4-\sqrt{2}+8=9\)
Khi x=9 thì \(A=\dfrac{3-1}{3-2}=\dfrac{2}{1}=2\)
b: \(P=B:A\)
\(=\dfrac{x-\sqrt{x}+2}{x-\sqrt{x}-2}:\dfrac{\sqrt{x}-1}{\sqrt{x}-2}\)
\(=\dfrac{x-\sqrt{x}+2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}\cdot\dfrac{\sqrt{x}-2}{\sqrt{x}-1}\)
\(=\dfrac{x-\sqrt{x}+1}{x-1}\)
c: \(P\cdot\sqrt{x}>=-\dfrac{3}{2}\)
=>\(\dfrac{x\sqrt{x}-x+\sqrt{x}}{x-1}+\dfrac{3}{2}>=0\)
=>\(\dfrac{2x\sqrt{x}-2x+2\sqrt{x}+3x-3}{2\left(x-1\right)}>=0\)
=>\(\dfrac{2x\sqrt{x}+x+2\sqrt{x}-1}{2\left(x-1\right)}>=0\)
TH1: \(\left\{{}\begin{matrix}2x\sqrt{x}+x+2\sqrt{x}-1>=0\\x-1>0\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}x>1\\x>=0,38\end{matrix}\right.\)
=>x>1
=>\(x\in N\backslash\left\{0;1;4\right\}\)
TH2: \(\left\{{}\begin{matrix}2x\sqrt{x}+x+2\sqrt{x}-1< =0\\x-1< 0\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}x< 1\\x< =0,38\end{matrix}\right.\)
=>0<=x<0,38
mà x nguyên
nên \(x=0\)