Which of the following is an identity?
A. sinBsecBcotB = 1
B. sinBsecBcotB = cotB
C. sinBsecBcotB = sin²B/cos²B

tan A - sec A =
A. Sin^2A - cosA/cosA
B. sinA-1/cosA
C. cos^2A - 1/cosA

1/1 - sinA + 1/1 + sinA =
A. 2 cos^2 A
B. 2 sec^2 A
C. tan^2 A
D. cot^2 A

If p(x) is the total value of the production when there are x workers in a plant, then the average productivity of the workforce at the plant is a(x) = p(x) x . (a) find a'(x). a'(x) = xp'(x) − p(x) x a'(x) = xp'(x) − p(x) x2 a'(x) = p'(x) − p(x) x a'(x) = xp'(x) − p'(x) x2 a'(x) = p'(x) − xp(x) x2 why does the company want to hire more workers if a'(x) > 0? a'(x) > 0 ⇒ a(x) is ; that is, the average productivity as the size of the workforce increases. (b) if p'(x) is greater than the average productivity, which of the following must be true? p'(x) − xp(x) > 0 p'(x) − xp(x) < 0 xp'(x) − p'(x) > 0 xp'(x) − p(x) < 0 xp'(x) − p(x) > 0