Solve the Problem $\mathrm { V } = 189 \sin 120 \pi \mathrm { t }$

Multiple Choice

Solve the problem.
-Suppose that for an electrical appliance, voltage is given by $\mathrm { V } = 189 \sin 120 \pi \mathrm { t }$ and amperage by $I = 1.07 \sin 120 \pi t$ , where $t$ is time in seconds. Use identities to write the wattage $W = V I$ in the form $\mathrm { W } = \mathrm { a } \cos \omega \mathrm { t } + \mathrm { c }$ .

A) $W = - 101.115 \cos 120 \pi t + 101.115$
B) $W = - 101.115 \cos 240 \pi t + 101.115$
C) $\mathrm { W } = - 202.23 \cos 240 \pi \mathrm { t } + 202.23$
D) $\mathrm { W } = 101.115 \cos 240 \pi t - 101.115$