1.
f (x) = (3x + 2)³·(2x - 1)⁴
f'(x) = 3·(3x + 2)²·3·(2x - 1)⁴ + (3x + 2)³·4·(2x - 1)³·2 = (3x + 2)²·(2x - 1)³·(9·(2x - 1) + 8·(3x + 2)) = (3x + 2)²·(2x - 1)³·(18x - 9 + 24x + 16) = (3x + 2)²·(2x - 1)³·(42x + 7) = 7·(3x + 2)²·(2x - 1)³·(6x + 1)
2.
f (x) = x² - x - 6
f'(x) = 2x - 1
Координаты x точек пересечения с Oх:
x² - x - 6 = 0
По теореме Виета:
x₁ = -2
x₂ = 3
Координата x точки пересечения с Oy: x₃ = 0.
f'(-2) = 2·(-2) - 1 = -5
f'(3) = 2·3 - 1 = 5
f'(0) = 2·0 - 1 = -1
3.
(cos 2x + 3·tg π/8)' ≥ 2·cos x
-2·sin 2x ≥ 2·cos x
-sin 2x ≥ cos x
cos x + sin 2x ≤ 0
cos x + 2·sin x·cos x ≤ 0
cos x·(1 + 2·sin x) ≤ 0
cos x ≤ 0 cos x ≥ 0
(1 + 2·sin x) ≥ 0 (1 + 2·sin x) ≤ 0
cos x ≤ 0 cos x ≥ 0
sin x ≥ -1/2 sin x ≤ -1/2
x ∈ [π/2 + 2πn; 3π/2 + 2πn], n ∈ Z x ∈ [-π/2 + 2πm; π/2 + 2πm], m ∈ Z
x ∈ [-π/6 + 2πk; 7π/6 + 2πk], k ∈ Z x ∈ [7π/6 + 2πp; 11π/6 + 2πp], p ∈ Z
x ∈ [π/2 + 2πn; 7π/6 + 2πn], n ∈ Z x ∈ [3π/2 + 2πk; 11π/6 + 2πk], k ∈ Z
x ∈ [π/2 + 2πn; 7π/6 + 2πn] ∪ [3π/2 + 2πn; 11π/6 + 2πn), n ∈ Z