Assume that a < b and let L be the arc length (circumference) of the ellipse (A) + () = 1 shown in Figure 2. There is 1-a/b. Use the first three no explicit formula for L, but it is known that L = 4bG(k), with G(k) as in Exercise 88 and k = terms of the expansion of Exercise 88 to estimate L when a = 4 and b = 5. y o FIGURE 2 The ellipse ( + () = = 1.