Числа : 556,656,565,665,566,655,
555,666
1) <span>1+сos2альфа/1- cos2альфа = 2cos^2 альфа/ 2sin^2 альфа = ctg^2 альфа</span>
<span><span><span> </span></span></span>
![\frac{1}{ctg (2x)-1}=0;\\ 1=0;](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7Bctg+%282x%29-1%7D%3D0%3B%5C%5C+1%3D0%3B)
решений нет
![\frac{1}{ctg (2x-1)}=0;\\ 1=0;](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7Bctg+%282x-1%29%7D%3D0%3B%5C%5C+1%3D0%3B)
решений нет
![\frac{1}{ctg (2x)}-1=0;\\ \frac{1}{ctg (2x)}=1;\\ ctg (2x)=\frac{1}{1};\\ ctg(2x)=1;\\ 2x=\frac{\pi}{4}+\pi*k;\\ x=\frac{\pi}{8}+\frac{\pi*k}{2}](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7Bctg+%282x%29%7D-1%3D0%3B%5C%5C+%5Cfrac%7B1%7D%7Bctg+%282x%29%7D%3D1%3B%5C%5C+ctg+%282x%29%3D%5Cfrac%7B1%7D%7B1%7D%3B%5C%5C+ctg%282x%29%3D1%3B%5C%5C+2x%3D%5Cfrac%7B%5Cpi%7D%7B4%7D%2B%5Cpi%2Ak%3B%5C%5C+x%3D%5Cfrac%7B%5Cpi%7D%7B8%7D%2B%5Cfrac%7B%5Cpi%2Ak%7D%7B2%7D)
k є Z
ответ: <var>
,k є Z</var>
2x² * 7xy² - 4xy² * (- xy) - 3x * 5x²y² = 14x³y² + 4x²y³ - 15x³y² =
= 4x²y² - x³y²