(8*cos(a)^3-4*cos(a))*sin(a)
-(4*cos(a)-8*cos(a)^3)*sin(a)
sin(4*a)
Решение смотри на фотографии
9-4х=5+14-6х -4х+6х=14+5-9 2х=10 <span>х=5</span>
F(x) = x^3 -27x -9
f'(x) = 3x^2 -27
3x^2 -27 = 0
x^2 -9 = 0
(x-3)(x+3) = 0
x = 3; x = -3
f'(-10) = 3*100 -27 = 273
f'(0) = 3*0 -27 = -27
f'(10) = 3*100 -27 = 273
__+__-3__-__3__+__
Ответ: -3.
Cos 9x ≥ 1/2
-π/3 +2πk ≤ 9x ≤ π/3 + 2πk , k ∈Z
-π/27 + 2πk/9 ≤ x ≤ π/27 + 2πk/9 , k ∈Z