Вместо а и б буду писать a и b
![\frac{a+b}{b}- \frac{a}{a+b}= \frac{ (a+b)^{2}-ab }{(a+b)b} = \frac{ a^{2}+2ab+ b^{2} -ab }{ab+ b^{2} } = \frac{a^{2}+ab+ b^{2}}{ab+ b^{2}}](https://tex.z-dn.net/?f=+%5Cfrac%7Ba%2Bb%7D%7Bb%7D-+%5Cfrac%7Ba%7D%7Ba%2Bb%7D%3D+%5Cfrac%7B+%28a%2Bb%29%5E%7B2%7D-ab+%7D%7B%28a%2Bb%29b%7D+%3D+%5Cfrac%7B+a%5E%7B2%7D%2B2ab%2B+b%5E%7B2%7D+-ab+%7D%7Bab%2B+b%5E%7B2%7D+%7D+%3D+%5Cfrac%7Ba%5E%7B2%7D%2Bab%2B+b%5E%7B2%7D%7D%7Bab%2B+b%5E%7B2%7D%7D+++)
Смотри ответ на картинке____________________________________________
4cosx - 4sinx - 4sin2x = 0
4cosx - 4sinx - 8sinxcosx = 0 | : 8cosx
2 - 4tgx - tgx = 0
2 - 5tgx = 0
-5tgx = -2
tgx = 2/5
x = arctg2/5 + Pi*n, n € Z
Cos(90-15)cos15= sin15cos15= ¹/₂ * 2sin15cos15= ¹/₂ sin(2*15)=
=¹/₂ sin30=¹/₂ * ¹/₂= 1/4
1) числитель 12 * М ^ 1/9 * М ^ 1/18 = 12 * М ^ ( 1/9 + 1/18 ) = 12 * М ^ 3/18 = 12 * М ^ ( 1/6 ) ;
2) ( 12 * М ^ 1/6 ) : М ^ ( 1/6 ) = 12 ;
ОТВЕТ 12