= 10.5+ (-18/5)(-143/45+89/60) = 10.5+(-18/5*(-143/45))+(-18/5*89/60) =
= 10.5 + 11.4 - 5.34 = 16.56
8- 4 ......................7- ещё не решила
Cos²A(1 + cos2A)²tg²A = cos²Asin²A/cos²A·(2cos²A - 1 + 1)² = sin²A·(2cos²A)² = 4cos⁴Asin²A = (2sinAcosA)²cos²A = sin²2Acos²A