Y` = (1 - (cos4x/sin4x))` = -(-4(sin4x)(sin4x) - 4(cos4x)(cos4x))/(sin4x)^2 =
= 4((sin4x)^2 - (cos4x)^2)/(sin4x)^2 = 4 - 4ctg4x
y` (-pi/8) = 4 - 4ctg(4*pi/8) = 4 - 4ctg(pi/2) = 4
1) 2аb-7ab+7a²= -5ab +7a²
2) 2a³+a²-17-3a²+a³-a-80= 3a³-2a²-97-a
10x + 2y = 84
2y = - 10x + 84
y = - 5x + 42 y = - 2,5x
- 5x + 42 = - 2,5x
- 5x + 2,5x = - 42
- 2,5x = - 42
x = 16,8
y = - 2,5 * 16,8 = - 42
Ответ: (16,8 ; - 42)
<span>4sin^3(2x)-3sin(2x)=0</span>