Without graphing the function, determine its amplitude or period as requested.
-$y = 4 \cos \frac { 1 } { 3 } x \quad$ Find the period.
A) 4
B) $\frac { 4 \pi } { 3 }$
C) $6 \pi$
D) $\frac { \pi } { 3 }$

Question

Quizplus · Accepted Answer

The period of a cosine function of the form $y = A \cos(Bx)$ is given by $T = \frac{2\pi}{|B|}$. Here, $B = \frac{1}{3}$, so the period is $T = \frac{2\pi}{1/3} = 6\pi$.

Without Graphing the Function, Determine Its Amplitude or Period as Requested