Question

for what part of the interval [-pi, pi] is y=-2sin x decreasing?

Answer 1

\[\int\limits y dx = 2cosx\] and that is negative when cosx is negative.
which is for -pi <=x <= -pi/2 and for pi/2 <= x <= pi

Answer 2

(sorry, not including pi/2 or -pi/2)

Answer 3

sorry, i forgot to include the answer choices: a) -pi/2, pi/2 b) -pi/3, pi/3 c) -pi/4, pi/4 d) -pi, 0 e) -pi, pi