Let and for . Which of the following lists all values of in this interval where the…

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

Problem

Let

x(t)=\sin t

and

y(t)=\cos 2t

for

0<t\le 2\pi

. Which of the following lists all values of

t

in this interval where the curve has a horizontal tangent? (a)

t=\dfrac{\pi}{2},\;\dfrac{3\pi}{2}

(b)

t=\dfrac{\pi}{2},\;\pi,\;\dfrac{3\pi}{2}

(c)

t=\pi,\;2\pi

(d)

t=\pi