(SinB + Cosb) / (SinB - CosB)^(-1) = -(CosB + SinM) * (CosB - SinB) = -(Cos^2 B - Sin^2B) = - Cos2B = - (1 - Sin^2 2B)^1/2 =
= -(1 - (-0.6)^2)^1/2 = - (1 - 0.36)^1/2 = -0.64^1/2 = -0.8
1) 7.1*10+8.9*15=71+133.5=204.5г (25 см^3 сплава)
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(sin(π/2-t)*tg(-t))/cos(π/2+t)=(-cost*tgt)/(-sint)=1