Explain why the condition is essential when writing for a parametric curve .

MATHEMATICS · Subjective · AP · Calculus BC · Parametric, Polar, and Vector-Valued Functions · Parametric, Polar, and Vector-Valued Functions

Problem

Explain why the condition

f'(t)\neq 0

is essential when writing

\dfrac{dy}{dx}=\dfrac{dy/dt}{dx/dt}

for a parametric curve

x=f(t),\;y=g(t)