Let d be the set of positive divisors of 12, ordered by divisibility, and let e be the set of even positive divisors of 12, ordered by divisibility.

a. (a) is d a boolean algebra? explain. you may appeal to facts from section 13.4.

b. (b) is e a boolean algebra? explain. do not appeal to facts from section 13.4

Need solving this second acceleration problem.

Aball is thrown from a height of 139 feet with an initial downward velocity of 15 ft/s. the ball's height h (in feet) after t seconds is given by the following. h=139-15t-16t^2 how long after the ball is thrown does it hit the ground? round your answer(s) to the nearest hundredth. (if there is more than one answer, use the "or" button.) t =

Atriangular field has sides of lengths 21, 39, and 41 yd. find the largest angle. (round your answer to the nearest degree.)