MATHEMATICS · Single correct · AP · Calculus AB · Differentiation: Composite, Implicit, and Inverse Functions · Differentiation: Composite, Implicit, and Inverse Functions
Problem
For an implicitly defined curve, the derivative can often be written in the form dxdy=D(x,y)N(x,y), where N and D are differentiable functions. Which condition must be satisfied at a point on the curve for the tangent line there to be
vertical?
(a) N(x,y)=0 and D(x,y)=0
(b) D(x,y)=0 and N(x,y)=0
(c) N(x,y)=0 and D(x,y)=0
(d) D(x,y)=0 (with no restriction on N(x,y))