Complex Power: \$S = V \cdot I^*\$ OR \$S = \frac{V \cdot I^*}{2}\$. Which formula is correct?
Both answers are correct, it's simply a matter of what \$V\$ and \$I\$ are supposed to represent. If they are the RMS value of voltages and current, then complex power is \$|S|=V\times I\$. If they instead represent a voltage amplitude (i.e. \$v(t)=V\cos(...)\$ and \$i(t)=I\cos(...)\$), then you must first take the RMS value by dividing amplitude by square root of 2. This leaves you with \$|S|=\frac{V}{\sqrt{2}}\times\frac{I}{\sqrt{2}}=\frac{V\times I}{2}\$.