Formula Sheet (taken principally from D. J. Griffiths: Introduction to Electrodynamics, Prentice Hall)

1

sin (2 ) = 2 sin ( ) cos( )

sin ( A B ) = sin ( A) cos(B ) cos( A) sin (B )

sin ( A) sin (B ) = 2 sin[1 ( A B )]cos[1 ( A B )] 2 2

cos( A B ) = cos( A) cos(B ) sin ( A)sin (B )

cos( A) + cos(B ) = 2 cos[1 ( A + B )]cos[1 ( A B )] 2 2

cos( A) cos(B ) = 2 sin[1 ( A + B )]sin[1 ( A B )] 2 2

2