\(A-1=\dfrac{\sqrt{x}-\sqrt{x}-3}{\sqrt{x}+3}=\dfrac{-3}{\sqrt{x}+3}< 0\)
=>A<1
\(A-1=\dfrac{\sqrt{x}-\sqrt{x}-3}{\sqrt{x}+3}=\dfrac{-3}{\sqrt{x}+3}< 0\)
=>A<1
B=\(\dfrac{\sqrt{x}}{\sqrt{x}+3}+\dfrac{6}{\sqrt{x}-1}-\dfrac{\sqrt{x}+15}{x+2\sqrt{ }x}-3\) Chứng minh B=\(\dfrac{\sqrt{x}+1}{\sqrt{x}-1}\) giúp mik câu này vs ạ mik đang cần gấp
B=\(\dfrac{2\sqrt{x}-3}{\sqrt{x}-1}\)+\(\dfrac{3-\sqrt{x}}{x-1}\)
chứng minh B=\(\dfrac{2\sqrt{x}}{\sqrt{x}+1}\)
Cho B=\(\dfrac{x+3}{x-9}+\dfrac{2}{3+\sqrt{x}}-\dfrac{1}{3-\sqrt{x}}\)
Chứng minh B= \(\dfrac{\sqrt{x}}{\sqrt{x}-3}\)
Help
\(B=\dfrac{3}{\sqrt{x}+1}+\dfrac{1}{1-\sqrt{x}}+\dfrac{x+5}{x-1}\)
Chứng minh rằng \(B=\dfrac{\sqrt{x}+1}{\sqrt{x}-1}\)
Cho A=\(\dfrac{\sqrt{x}+1}{\sqrt{x}-1}\)
B=\(\dfrac{\sqrt{x}-1}{\sqrt{x}+1}-\dfrac{3\sqrt{x}+1}{x-1}\)
Chứng minh A+B= \(\dfrac{2\sqrt{x}-1}{\sqrt{x}+1}\)
Help
Chứng minh đẳng thức sau:
1) \(\dfrac{2+\sqrt{3}}{\sqrt{2}+\sqrt{2+\sqrt{3}}}+\dfrac{2-\sqrt{3}}{\sqrt{2}-\sqrt{2-\sqrt{3}}}=\sqrt{2}\)
2) \(\left(\sqrt{x}-\dfrac{x}{x+\sqrt{x}}\right):\left(\dfrac{\sqrt{x}-1}{x\sqrt{x}-\sqrt{x}}\right)=x\sqrt{x}\left(x>0;x\ne1\right)\)
Cho \(x=\dfrac{\sqrt{2}-\sqrt{1}}{1+\sqrt{2}}+\dfrac{\sqrt{3}-\sqrt{2}}{2+\sqrt{3}}+\dfrac{\sqrt{4}-\sqrt{3}}{3+4}+...+\dfrac{\sqrt{100}-\sqrt{99}}{99+100}\). Chứng minh \(x< \dfrac{1}{2}\)
CHỨNG MINH RẰNG
P=\(\left(\dfrac{\sqrt{x}}{\sqrt{x}+3}+\dfrac{3}{\sqrt{x}-3}\right)\)x\(\dfrac{\sqrt{x}+3}{x+9}\)=\(\dfrac{1}{\sqrt{x}-3}\) với x\(\ge\)0 và x\(\ne\)9
Cho Q= \(\dfrac{\sqrt{x}-1}{\sqrt{x}+4}\) + \(\dfrac{9\sqrt{x}-4}{x-16}\) - \(\dfrac{4\sqrt{x}-4x}{\sqrt{x}-4}\)
Chứng minh Q= \(\dfrac{x-3\sqrt{x}}{\sqrt{x}-4}\)
Cho \(x=\dfrac{\sqrt{2}-1}{1+2}+\dfrac{\sqrt{3}-\sqrt{2}}{2+3}+\dfrac{\sqrt{4}-\sqrt{3}}{3+4}+...+\dfrac{\sqrt{225}-\sqrt{224}}{224+225}\) . Chứng minh rằng \(x< \dfrac{7}{15}\) .