This chapter discusses sinusoidal steady state power calculations. Numerical integration is used to obtain the rms value, average power and quadrature power. Three-phase circuits are analyzed by converting the circuits into the frequency domain and by using the Kirchoff voltage and current laws. The unknown voltages and currents are solved using matrix techniques. Given a network function or transfer function, MATLAB has functions that can be used to (i) obtain the poles and zeros, (ii) perform