Let the range of the function f(x)=6+16 cos x·cos(π3–x)·cos(π3+x)·sin 3x·cos 6x, x∈R be [α, β]. Then the distance of the point (α, β) from the line 3x + 4y + 12 = 0 is: [2025]
(2)
f(x)=6+16(14cos 3x) sin 3x·cos 6x
[∵ cos θ cos(π3–θ)cos(π3+θ)=14cos 3θ]
=6+4 cos 3x sin 3x cos 6x=6+sin 12x
∵ Range of sin x = [–1, 1]
∴ Range of f(x) is [5, 7]
⇒ (α,β)≡(5,7)
∴ Distance of point (5, 7) from the line 3x + 4y + 12 = 0
=|15+28+125|=11