Q. Briefly explain about Phasor Method?

For sinusoidal excitations of the same frequency, the forced or steady-state responses are better found by the technique known as the phasormethod. Time functions are transformed to the phasor representations of the sinusoids. For example, current and voltage in the time domain are given by the forms

and where Re stands for the "real part of"; their corresponding phasors in the frequency domain are defined by

Notice that the magnitudes of the phasors are chosen for convenience to be the rms values of the original functions (rather than the peak amplitudes), and angles are given by the argument of the cosine function at t = 0. The student should observe that phasors are referenced here to cosine functions. Therefore, the conversion of sine functions into equivalent cosine functions makes it more convenient for expressing phasor representations of sine functions.