If the current and voltage of an electrical device (in the passive reference configuration) are
\( v ( t ) = 6 \sin ( 100 \pi t ) V \) and \( i ( t ) = 10 \sin ( 100 \pi t ) + 9 \cos ( 100 \pi t ) A \) . Then the average power delivered to the device over a \( 20 \) ms interval (i.e. one period of the current and voltage waveform) (computed to one decimal place) is given by