19. Find the terms of the Maclaurin series for  , as far as the term in x3 . 

(A) 1 - x + x2 -x3
(B) 1 + x - 1/2 x2 + 1/3 x3
(C) 1 - x + 3/2 x2 - 5/2 x3
(D) 1 + x + 3x2 + 5 x3
(E) 1 - x + 3/2 x2 - 7/3 x3