The position of a particle is given parametrically by
MATHEMATICS · Single correct · AP · Calculus AB · Differentiation: Composite, Implicit, and Inverse Functions · Differentiation: Composite, Implicit, and Inverse Functions
Problem
The position of a particle is given parametrically by y=f(x), where f′(x)>0 for all x, and x(t)=e−t for t>0. Which statement best describes the sign of dtdy for t>0?
(a) dtdy>0 for all t>0
(b) dtdy<0 for all t>0
(c) dtdy=0 for all t>0
(d) The sign of dtdy depends on f′′(x)