1)2,781/2,06=1,35
2)7,825/3,13=2,5
3)1,35+2,5=3,85
Sin 7π/3 = sin (2π + π/3) = sin π/3 = sqrt3/2
cos 7π/3 = cos (2π + π/3) = cos π/3 = 1/2
tg 7π/3 = tg (2•π + π/3) = tg π/3 = sqrt3
ctg 7π/3 = ctg (2•π + π/3) = ctg π/3 = sqrt3/3
<span>приведём дроби 17/24 и 15/26 к общему знаменателю</span>