This document is from Chapter 13 of the textbook "Introductory Circuit Analysis" by Boylestad. It discusses sinusoidal alternating waveforms, including their characteristics and definitions. Some key points covered include: the objectives of becoming familiar with sinusoidal waveforms and their parameters like frequency and phase relationships; defining characteristics of sinusoidal voltages like peak amplitude and period; discussing average and effective (RMS) values; and examples of analyzing sinusoidal waveforms using concepts like phase shifts. The chapter contains numerous figures and examples to illustrate sinusoidal concepts.