Determine the Equation of the Graph $\mathrm { s } ( \mathrm { t } ) = - 2 \cos 7 \mathrm { t }$

Multiple Choice

Determine the equation of the graph.
-The position of a weight attached to a spring is $\mathrm { s } ( \mathrm { t } ) = - 2 \cos 7 \mathrm { t }$ inches after $\mathrm { t }$ seconds. What are the frequency and period of the system?

A) Frequency $= \frac { \pi } { 7 }$ cycles per sec, period $= \frac { 7 } { \pi } \mathrm { sec }$
B) Frequency $= \frac { 7 } { 2 \pi }$ cycles per sec, period $= \frac { 2 \pi } { 7 } \mathrm { sec }$
C) Frequency $= \frac { 7 } { \pi }$ cycles per sec, period $= \frac { \pi } { 7 } \mathrm { sec }$
D) Frequency $= 7$ cycles per sec, period $= \frac { 1 } { 7 } \mathrm { sec }$