Solve the Problem $\mathrm { I } ( \mathrm { t } ) = 5 \cos ( 120 \pi \mathrm { t } )$

Multiple Choice

Solve the problem.

-Suppose that a household appliance draws a current represented by the relation $\mathrm { I } ( \mathrm { t } ) = 5 \cos ( 120 \pi \mathrm { t } )$ , where $t$ is time measured in seconds. The power consumed by the appliance is $\mathrm { P } = \mathrm { I } ^ { 2 } \mathrm { R }$ , where $\mathrm { R }$ is a constant. Take R to be 12 and graph the power in [0, 0.04, 0.01] by $[ - 200,2000,200 ]$ and use an identity to write the expression for the power in the form $\mathrm { P } = \mathrm { a } \cos ( \mathrm { k } \pi \mathrm { t } ) + \mathrm { d }$ , where $a , k$ , and $d$ are constants.

A) $P = 150 \cos ( 120 \pi t ) + 150$
$[ 0,0.04,0.01 ]$ by $[ - 200,2000,200 ]$


B) $P = - 150 \cos ( 240 \pi t ) + 150$
$[ 0,0.04,0.01 ]$ by $[ - 200,2000,200 ]$

C) $\mathrm { P } = 150 \cos ( 240 \pi \mathrm { t } ) + 150$
$[ 0,0.04,0.01 ]$ by $[ - 200,2000,200 ]$


D) $\mathrm { P } = 300 \cos ( 240 \pi \mathrm { t } ) + 300$
$[ 0,0.04,0.01 ]$ by $[ - 200,2000,200 ]$