$2\left ( \sqrt{1-x} -\sqrt{x+2}\right )=5+2\sqrt{2-x-x^{2}}$
Giải phương trình : $2\left ( \sqrt{1-x} -\sqrt{x+2}\right )=5+2\sqrt{2-x-x^{2}}$
Started By hoaadc08, 10-04-2014 - 21:19
#1
Posted 10-04-2014 - 21:19
#2
Posted 10-04-2014 - 21:35
$2\left ( \sqrt{1-x} -\sqrt{x+2}\right )=5+2\sqrt{2-x-x^{2}}$
C1:
đặt:
$\sqrt{1-x}-\sqrt{x+2}=t\Rightarrow 2\sqrt{2-x-x^2}=3-t^2$
thế vào phương trình là OK!!!!
C2: đưa về hệ:
đặt: $\left\{\begin{matrix} \sqrt{1-x}=a & \\ \sqrt{x+2}=b& \end{matrix}\right. \Rightarrow \left\{\begin{matrix} 2(a-b)=5+2ab & \\ a^2+b^2=3 & \end{matrix}\right.$
Edited by Kaito Kuroba, 10-04-2014 - 21:38.
- hoctrocuanewton and Nguyen Huy Hoang like this
#3
Posted 11-04-2014 - 09:38
PT vô nghiệm vì : max VT = $2\sqrt{3}$ < 5 = min VP
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