1.
Let the range of the function
f(x)=6+16cosxcos(π3x)cos(π3+x)sin3xcos6x,xRf(x)=\frac{6+16\cos x\cos\left(\frac{\pi}{3}-x\right)\cos\left(\frac{\pi}{3}+x\right)}{\sin3x\cos6x},\quad x\in\mathbb R
be [a,b][a,b]. Then the distance of the point (a,b)(a,b) from the line 3x+4y+12=03x+4y+12=0 is: