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AP® Calculus AB-BC

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Moderate

Speed With Trig Function

APCALC-W8UEWB

A particle moves in the $xy$-plane for time $t>0$ according to the position equations $x( t ) =\tan { ( t ) },\ y( t ) =1-3t$. Determine the speed of the particle at $t=\cfrac{\pi}{3}$.

A

$25$

B

$5$

C

$\sqrt 5$

D

$\sqrt 7$