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YenThanh2

YenThanh2

Đăng ký: 09-12-2011
Offline Đăng nhập: 19-04-2013 - 03:18
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$ \left\{\begin{array}{l}| y+\frac...

17-07-2012 - 14:51

$$ \left\{\begin{array}{l}\left | y+\frac{1}{x} \right |+\left | \frac{13}{16}+x-y \right |=-x-\frac{1}{x}-\frac{13}{16}\\x^{2}+y^{2}=\frac{97}{36}\\ x<0,y>0\end{array}\right. $$

Giải hệ $$\left\{\begin{matrix} x+y+z=xyz\\ x(y^{2}-...

15-07-2012 - 08:42

$$\left\{\begin{matrix}
x+y+z=xyz\\ x(y^{2}-1)(z^{2}-1)+y(x^{2}-1)(z^{2}-1)+z(x^{2}-1)(y^{2}-1)=0

\end{matrix}\right.$$

$\begin{cases}x^6+\frac{2xy}{\sqrt[5]...

14-07-2012 - 17:02

$$\left\{\begin{matrix}
x^{6}+\frac{2xy}{\sqrt[5]{x^{2}-2x+33}}=x^{2}+y^{6}\\
y^{6}+\frac{2xy}{\sqrt[5]{y^{2}-2y+33}}=y^{2}+x^{6}
\end{matrix}\right.$$

\[\cos \left( {\frac{\pi }{4} + 2x} \right)\cos...

09-05-2012 - 16:25

$$cos\left(\frac{\Pi }{4} +2x\right)cos\left(\frac{\Pi }{4} -2x\right)+{sin}^{2}x\left(cos2x+1 \right)=\frac{1}{4}$$
với $x\in \left[\frac{-\Pi }{4};\frac{\Pi }{4} \right]$

$\cot \frac{x}{2}-\frac{1+\cos 3x}{\sin 2x - \sin x}...

09-05-2012 - 16:22

$\cot \frac{x}{2}-\frac{1+\cos 3x}{\sin 2x - \sin x}=2\sin\left(3x+\frac{\pi}{3} \right)$