Пошаговое объяснение:
делим все на cos^2x
получим:
https://tex.z-dn.net/?f=%5Cfrac%7B2sin%5E2x%7D%7Bcos%5E2x%7D%20%2B%20%5Cfrac%7Bsinx*cosx%7D%7Bcos%5E2x%7D%20-%20%5Cfrac%7Bcos%5E2x%7D%7Bcos%5E2x%7D%20%3D0%20%5C%5C2*(%20%5Cfrac%7Bsinx%7D%7Bcosx%7D%20)%5E2%2B(%20%5Cfrac%7Bsinx%7D%7Bcosx%7D%20)-1%3D0%20%5C%5C2tg%5E2x%2Btgx-1%3D0%20%5C%5Ctgx%3Dy%20%5C%5C2y%5E2%2By-1%3D0%20%5C%5CD%3D1%2B8%3D9%3D3%5E2%20%5C%5Cy_1%3D%20%5Cfrac%7B-1%2B3%7D%7B4%7D%20%3D%20%5Cfrac%7B1%7D%7B2%7D%20%5C%5Cy_2%3D%20%5Cfrac%7B-1-3%7D%7B4%7D%20%3D-1%20%5C%5Ctgx%3D%5Cfrac%7B1%7D%7B2%7D%20%5C%5Cx_1%3Darctg(%20%5Cfrac%7B1%7D%7B2%7D%20)%2B%5Cpi%20n%2C%5C%20n%20%5Cin%20Z%20%5C%5Ctgx%3D-1%20%5C%5Cx_2%3D%20-%5Cfrac%7B%5Cpi%7D%7B4%7D%20%2B%5Cpi%20n%2C%5C%20n%20%5Cin%20Z перейди по ней тут ответ
50 станков.