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Cosx≠1/2, cosx≠0
![frac{4cosx-5}{2cosx-1} + frac{1}{2cos^2x-cosx} =2 \ frac{4cosx-5}{2cosx-1} + frac{1}{cosx (2cosx-1)} =2 \ frac{cosx(4cosx-5)}{cosx (2cosx-1)} + frac{1}{cosx (2cosx-1)} =2 \ frac{cosx(4cosx-5)+1}{cosx (2cosx-1)} =2 frac{4cosx-5}{2cosx-1} + frac{1}{2cos^2x-cosx} =2 \ frac{4cosx-5}{2cosx-1} + frac{1}{cosx (2cosx-1)} =2 \ frac{cosx(4cosx-5)}{cosx (2cosx-1)} + frac{1}{cosx (2cosx-1)} =2 \ frac{cosx(4cosx-5)+1}{cosx (2cosx-1)} =2](https://tex.z-dn.net/?f=+frac%7B4cosx-5%7D%7B2cosx-1%7D+%2B+frac%7B1%7D%7B2cos%5E2x-cosx%7D+%3D2+%5C++frac%7B4cosx-5%7D%7B2cosx-1%7D+%2B+frac%7B1%7D%7Bcosx+%282cosx-1%29%7D+%3D2+%5C++frac%7Bcosx%284cosx-5%29%7D%7Bcosx+%282cosx-1%29%7D+%2B+frac%7B1%7D%7Bcosx+%282cosx-1%29%7D+%3D2+%5C++frac%7Bcosx%284cosx-5%29%2B1%7D%7Bcosx+%282cosx-1%29%7D++%3D2)
cosx(4cosx-5)+1 =2cosx (2cosx-1)
4cos²x-5cosx+1=4cos²x-2cosx
5cosx-2cosx=1
3cosx=1
cosx=1/3
x=+-arccos (1/3)+2πn
б)
х=+arccos (1/3)-4π
cosx(4cosx-5)+1 =2cosx (2cosx-1)
4cos²x-5cosx+1=4cos²x-2cosx
5cosx-2cosx=1
3cosx=1
cosx=1/3
x=+-arccos (1/3)+2πn
б)
х=+arccos (1/3)-4π
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