<h3>sin( п + а ) / sin ( п/2 + а ) = - sina / cosa = - tga = - tg( п/4 ) = - 1</h3><h3 /><h3><em>Ответ: - 1</em></h3>
Хкм/ч собственная скорость,укм/ч скорость течения
{48/(x-y)+30/(x+y)=3⇒3(x²-y²)=48(x+y)+30(x-y)⇒3(x²-y²)=78x+18y
{36/(x-y)-15/(x+y)=1⇒x²-y²=36(x+y)-15(x-y)⇒x²-y²=21x+51y
3*(21x+51y)=78x+18y
63x+153y=21x+51y
153y-18y=78x-63x
13y=15x
x=9y
81y²-y²=189y+51y
80y²-240y=0
80y(y-3)=0
y=0 не удов усл
у=3км/ч скорость течения
3*9=27км/ч собственная скорость
1) y = 7 + 12x - x^3
x1 = -2
y = 7 - 12*2 + 2^3 = 7 - 24 + 8= -9
x2 = -1
y = 7 - 12 + 1 = 8 - 12 = -4
x3 = 0
y = 7 + 12*0 - 0 = 7
x4 = 1
y = 7 + 12 - 1 = 19 - 1 = 18
x5 = 2
y = 7 + 12*2 - 2^3 = 7 + 24 - 8 = 24 - 1 = 23
Ответ у = 23
2) y = (x - 8) * c^(x - 7)
x1 = 6
y = (6 - 8) * c^(6 - 7) = -2/c^2
x2 = 7
y = (7 - 8)*c^(7 - 7) = -1*1 = -1
x3 = 8
y = (8 - 8)*c(8 - 7) = 0
Ответ 0
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