1+2sinx=sin^2(х/2)+cos^2(х/2)+2sin2•х/2=
sin^2(х/2)+cos^2(х/2)+2sinх/2cosx/2=(sinx/2+соsx/2)^2
Tg(b + pi/3) = 2√3
tg(b + pi/3) = (tgb + tg(pi/3))/(1 - tgb*tg(pi/3)) = (tgb + √3) / (1 - √3*tgb) = 2√3
ctgb = 1/tgb
(tgb + √3) / (1 - √3*tgb) = 2√3
2√3*(1 - √3*tgb) = tgb + √3
2√3 - 6tgb = tgb + √3
7tgb = √3
tgb = √3/7
ctgb = 7/√3
2100-80-3=2017
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3(2-0,3)^2-3(0,3+2)(2-0.3) 3(4-1.2+0.09)-(0.9+6)(2-0.3) (12- 3.6+0,27)-(1.8-0.27+12-1.8) 12-3.6+0.27-1.8-0.27-12+1.8=-1,8 Ответ -1.8
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