ABSTRACT
At the end of this chapter, you should be able to:
• sketch sine, cosine and tangent waveforms • determine angles of any magnitude • understand cycle, amplitude, period, periodic time, frequency, lagging/leading angles with reference to sine
and cosine waves • perform calculations involving sinusoidal form A sin(ωt ±α) • define a complex wave and harmonic analysis
By drawing up tables of values from 0◦ to 360◦, graphs of y = sin A, y = cos A and y = tan A may be plotted. Values obtained with a calculator (correct to 3 decimal places — which is more than sufficient for plotting graphs), using 30◦ intervals, are shown below, with the respective graphs shown in Fig. 23.1. (a) y = sin A
From Fig. 23.1 it is seen that: (i) Sine and cosine graphs oscillate between peak
(ii) The cosine curve is the same shape as the sine curve but displaced by 90◦.
