11 13 17 Write a recursive formula for the arithmetic sequence {a,} = 3, 3' 3 5, ... O A. a = 3, an = + WIN O B. a = 3, an = WIN + W/y O C. a = 3, an = an-it WIN O D. a = 3, an = antArope is swinging in such a way that the length of the arc traced by a knot at its bottom end is decreasing geometrically. It the third arc is 13 it. long and the seventh are is 8 ft long. what is the length of the are on the sixth swing? Round your answer to the nearest tenth of a foot. 0 A. 14.? . 0 B. 12.0 . 0 C. 10.5 . 0 D. 9.3 it