Determine the value of cos(15∘)\cos(15^\circ)cos(15∘) by using the half-angle formula for cos(30∘/2)\cos(30^\circ/2)cos(30∘/2).
6−24\frac{\sqrt{6}-\sqrt{2}}{4}46−2
6+24\frac{\sqrt{6}+\sqrt{2}}{4}46+2
2+12\frac{\sqrt{2}+1}{2}22+1
3−12\frac{\sqrt{3}-1}{2}23−1