The polarity marks for all three voltage sources are oriented in such a way that their stated voltages
should add to make the total voltage across the load resistor. Notice that although magnitude
and phase angle is given for each AC voltage source, no frequency value is specified. If this is the
case, it is assumed that all frequencies are equal, thus meeting our qualifications for applying DC
rules to an AC circuit (all figures given in complex form, all of the same frequency). The setup of
our equation to find total voltage appears as such: