![\dfrac{a(1-2a)+2ax}{2ax+2a^2-1} <0\\ \dfrac{a-2a^2+2ax}{2a^2+2ax-1}<0\\ \dfrac{2a^2+2ax-1-4a^2+a+1}{2a^2+2ax-1} <0\\ 1-\dfrac{4a^2-a-1}{2a^2+2ax-1} <0 \dfrac{a(1-2a)+2ax}{2ax+2a^2-1} <0\\ \dfrac{a-2a^2+2ax}{2a^2+2ax-1}<0\\ \dfrac{2a^2+2ax-1-4a^2+a+1}{2a^2+2ax-1} <0\\ 1-\dfrac{4a^2-a-1}{2a^2+2ax-1} <0](https://tex.z-dn.net/?f=+%5Cdfrac%7Ba%281-2a%29%2B2ax%7D%7B2ax%2B2a%5E2-1%7D+%3C0%5C%5C+%5Cdfrac%7Ba-2a%5E2%2B2ax%7D%7B2a%5E2%2B2ax-1%7D%3C0%5C%5C++%5Cdfrac%7B2a%5E2%2B2ax-1-4a%5E2%2Ba%2B1%7D%7B2a%5E2%2B2ax-1%7D+%3C0%5C%5C+1-%5Cdfrac%7B4a%5E2-a-1%7D%7B2a%5E2%2B2ax-1%7D+%3C0+)
Рассмотрим функцию
![f(x)=1-\dfrac{4a^2-a-1}{2a^2+2ax-1} f(x)=1-\dfrac{4a^2-a-1}{2a^2+2ax-1}](https://tex.z-dn.net/?f=+f%28x%29%3D1-%5Cdfrac%7B4a%5E2-a-1%7D%7B2a%5E2%2B2ax-1%7D+)
Она имеет разрыв при
![2a^2+2ax-1=0 \ \ \ \Rightarrow \ \ \ x=\dfrac{1-2a^2}{2a} 2a^2+2ax-1=0 \ \ \ \Rightarrow \ \ \ x=\dfrac{1-2a^2}{2a}](https://tex.z-dn.net/?f=+2a%5E2%2B2ax-1%3D0+%5C+%5C+%5C+%5CRightarrow+%5C+%5C+%5C+x%3D%5Cdfrac%7B1-2a%5E2%7D%7B2a%7D++)
"Вытолкнем" разрыв за пределы отрезка [-2; 2]
2 \end{array}} \ \Leftrightarrow \ \left[\begin{array}{I} \dfrac{2a^2-4a-1}{2a}>0 \\ \dfrac{2a^2+4a-1}{2a}<0 \end{array}} \ \Leftrightarrow \ \left[\begin{array}{I} a \in \left(\dfrac{2- \sqrt{6}}{2}; \ 0 \right) \cup \left(\dfrac{2+ \sqrt{6}}{2}; \ + \infty \right) \\ a \in \left(- \infty; \ \dfrac{-2-\sqrt{6}}{2} \right) \cup \left( 0; \ \dfrac{-2+ \sqrt{6}}{2} \right) \end{array}}\\ " alt=" \left[\begin{array}{I} \dfrac{1-2a^2}{2a}<-2 \\ \dfrac{1-2a^2}{2a}>2 \end{array}} \ \Leftrightarrow \ \left[\begin{array}{I} \dfrac{2a^2-4a-1}{2a}>0 \\ \dfrac{2a^2+4a-1}{2a}<0 \end{array}} \ \Leftrightarrow \ \left[\begin{array}{I} a \in \left(\dfrac{2- \sqrt{6}}{2}; \ 0 \right) \cup \left(\dfrac{2+ \sqrt{6}}{2}; \ + \infty \right) \\ a \in \left(- \infty; \ \dfrac{-2-\sqrt{6}}{2} \right) \cup \left( 0; \ \dfrac{-2+ \sqrt{6}}{2} \right) \end{array}}\\ " align="absmiddle" class="latex-formula">
![a \in \left(- \infty; \ \dfrac{-2-\sqrt{6}}{2} \right) \cup \left( \dfrac{2- \sqrt{6}}{2}; \ 0 \right) \cup \left( 0; \ \dfrac{-2+ \sqrt{6}}{2} \right) \cup \left(\dfrac{2+\sqrt{6}}{2}; \ + \infty \right) a \in \left(- \infty; \ \dfrac{-2-\sqrt{6}}{2} \right) \cup \left( \dfrac{2- \sqrt{6}}{2}; \ 0 \right) \cup \left( 0; \ \dfrac{-2+ \sqrt{6}}{2} \right) \cup \left(\dfrac{2+\sqrt{6}}{2}; \ + \infty \right)](https://tex.z-dn.net/?f=+a+%5Cin+%5Cleft%28-+%5Cinfty%3B+%5C+%5Cdfrac%7B-2-%5Csqrt%7B6%7D%7D%7B2%7D+%5Cright%29+%5Ccup+%5Cleft%28+%5Cdfrac%7B2-+%5Csqrt%7B6%7D%7D%7B2%7D%3B+%5C+0+%5Cright%29+%5Ccup+%5Cleft%28+0%3B+%5C+%5Cdfrac%7B-2%2B+%5Csqrt%7B6%7D%7D%7B2%7D+%5Cright%29+%5Ccup+%5Cleft%28%5Cdfrac%7B2%2B%5Csqrt%7B6%7D%7D%7B2%7D%3B+%5C+%2B+%5Cinfty+%5Cright%29+++)
получили ограничения по a.
Вернемся к функции. Заметим, что она монотонна ⇒ если f(-2)<0 и f(2)<0, то при любом x из отрезка [-2; 2] функция принимает отрицательные значения.</strong>
0 \\ \dfrac{a(2a-5)}{2a^2+4a-1}>0 \end{array}} \ \Leftrightarrow \\ " alt=" \left\{\begin{array}{I} \dfrac{-2a^2-3a}{2a^2-4a-1}<0 \\ \dfrac{-2a^2+5a}{2a^2+4a-1}<0 \end{array}} \ \Leftrightarrow \ \left\{\begin{array}{I} \dfrac{a(2a+3)}{2a^2-4a-1}>0 \\ \dfrac{a(2a-5)}{2a^2+4a-1}>0 \end{array}} \ \Leftrightarrow \\ " align="absmiddle" class="latex-formula">
![\Leftrightarrow \ \left\{\begin{array}{I} a \in (- \infty; \ -1,5) \cup \left( \dfrac{2- \sqrt{6}}{2}; \ 0 \right) \cup \left(\dfrac{2+ \sqrt{6}}{2}; \ + \infty \right) \\ a \in \left(- \infty; \ \dfrac{-2-\sqrt{6}}{2} \right) \cup \left(0; \ \dfrac{-2+ \sqrt{6}}{2} \right) \cup (2,5; \ + \infty) \end{array}} \Leftrightarrow \ \left\{\begin{array}{I} a \in (- \infty; \ -1,5) \cup \left( \dfrac{2- \sqrt{6}}{2}; \ 0 \right) \cup \left(\dfrac{2+ \sqrt{6}}{2}; \ + \infty \right) \\ a \in \left(- \infty; \ \dfrac{-2-\sqrt{6}}{2} \right) \cup \left(0; \ \dfrac{-2+ \sqrt{6}}{2} \right) \cup (2,5; \ + \infty) \end{array}}](https://tex.z-dn.net/?f=+%5CLeftrightarrow+%5C+%5Cleft%5C%7B%5Cbegin%7Barray%7D%7BI%7D+a+%5Cin+%28-+%5Cinfty%3B+%5C+-1%2C5%29+%5Ccup+%5Cleft%28+%5Cdfrac%7B2-+%5Csqrt%7B6%7D%7D%7B2%7D%3B+%5C+0+%5Cright%29+%5Ccup+%5Cleft%28%5Cdfrac%7B2%2B+%5Csqrt%7B6%7D%7D%7B2%7D%3B+%5C+%2B+%5Cinfty+%5Cright%29+%5C%5C+a+%5Cin+%5Cleft%28-+%5Cinfty%3B+%5C+%5Cdfrac%7B-2-%5Csqrt%7B6%7D%7D%7B2%7D+%5Cright%29+%5Ccup+%5Cleft%280%3B+%5C+%5Cdfrac%7B-2%2B+%5Csqrt%7B6%7D%7D%7B2%7D+%5Cright%29+%5Ccup+%282%2C5%3B+%5C+%2B+%5Cinfty%29+%5Cend%7Barray%7D%7D+++++++)
![a \in \left( - \infty; \ \dfrac{-2-\sqrt{6}}{2} \right) \cup (2,5; \ + \infty) a \in \left( - \infty; \ \dfrac{-2-\sqrt{6}}{2} \right) \cup (2,5; \ + \infty)](https://tex.z-dn.net/?f=+a+%5Cin+%5Cleft%28+-+%5Cinfty%3B+%5C+%5Cdfrac%7B-2-%5Csqrt%7B6%7D%7D%7B2%7D+%5Cright%29+%5Ccup+%282%2C5%3B+%5C+%2B+%5Cinfty%29++)
Решение полностью попадает в ранее найденные ограничения.
Ответ: ![a \in \left( - \infty; \ \dfrac{-2-\sqrt{6}}{2} \right) \cup (2,5; \ + \infty) a \in \left( - \infty; \ \dfrac{-2-\sqrt{6}}{2} \right) \cup (2,5; \ + \infty)](https://tex.z-dn.net/?f=+a+%5Cin+%5Cleft%28+-+%5Cinfty%3B+%5C+%5Cdfrac%7B-2-%5Csqrt%7B6%7D%7D%7B2%7D+%5Cright%29+%5Ccup+%282%2C5%3B+%5C+%2B+%5Cinfty%29+)
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![2a^2+4a-1=0\\ \frac{D}{4}=4+2=6\\ a=\dfrac{-2 \pm \sqrt{6}}{2}\\ \\ 2a^2-4a-1=0\\ \frac{D}{4}=4+2=6\\ a=\dfrac{2 \pm \sqrt{6}}{2} 2a^2+4a-1=0\\ \frac{D}{4}=4+2=6\\ a=\dfrac{-2 \pm \sqrt{6}}{2}\\ \\ 2a^2-4a-1=0\\ \frac{D}{4}=4+2=6\\ a=\dfrac{2 \pm \sqrt{6}}{2}](https://tex.z-dn.net/?f=+2a%5E2%2B4a-1%3D0%5C%5C+%5Cfrac%7BD%7D%7B4%7D%3D4%2B2%3D6%5C%5C++a%3D%5Cdfrac%7B-2+%5Cpm+%5Csqrt%7B6%7D%7D%7B2%7D%5C%5C++%5C%5C+2a%5E2-4a-1%3D0%5C%5C+%5Cfrac%7BD%7D%7B4%7D%3D4%2B2%3D6%5C%5C++a%3D%5Cdfrac%7B2+%5Cpm+%5Csqrt%7B6%7D%7D%7B2%7D++)