Referring to Figure 12, let a be the length of the chord AC of angle d of the unit circle. Derive the following approximation for the excess of the arc over the chord: 93 0 - a 24 Hint: Show that 0 - a = 0 - 2 sin(0/2) and use the third Maclaurin poly- nomial as an approximation. B b A FIGURE 12 Unit circle