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AP® Calculus AB-BC

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Moderate

Angle Of Elevation

APCALC-SEDBL1

A child standing $4$ feet away from his mother lets go of his balloon at the same height as his mother’s line of sight. The balloon is rising at a rate of $1$ foot per second.

How fast is the angle of elevation from the mother to the balloon changing $3$ seconds later?

A

$5 \cfrac {\text{radian}} {\text {sec}}$.

B

$3 \cfrac {\text{radian}} {\text {sec}}$.

C

$1 \cfrac {\text{radian}} {\text {sec}}$.

D

$\cfrac {4}{25} \cfrac {\text{radian}} {\text {sec}}$.