USEFUL TRIGONOMETRIC IDENTITIES
A.1 BASIC IDENTITIES
A number of basic trigonometric identities that have gone into the development of the discussions in this book are presented here.
For any real numbers x and y,
By combining pairs of the above relationships, the following identities are obtained.
And, from these relationships, recalling that sin(0) = 0 and cos(0) = 1, if y = x, then
From Eqs. ...