sin ( + ) = sin cos + cos sin
cos ( + ) = cos cos - sin sin
tan ( + ) = (tan + tan )/(1 - tan tan )
cot ( + ) = (cot cot - 1)/(cot + cot )
sin ( - ) = sin cos - cos sin
cos ( - ) = cos cos + sin sin
tan ( - ) = (tan - tan )/(1 + tan tan )
cot ( - ) = (cot cot + 1)/(cot - cot )
sin 2 = 2 sin cos
cos 2 = cos2 - sin2 = 1 - 2 sin2 = 2 cos2 - 1
tan 2 = (2 tan )/(1 - tan2)
cot 2 = (cot2 - 1)/(2 cot )
sin (/2) = ±
cos (/2) = ±
tan (/2) = ±
cot (/2) = ±
sin sin = (1/2)[cos ( - ) - cos ( + )]
cos cos = (1/2)[cos ( - ) + cos ( + )]
sin cos = (1/2)[sin ( + ) + sin ( - )]
sin + sin = 2 sin (1/2)( + ) cos (1/2)( - )
sin - sin = 2 cos (1/2)( + ) sin (1/2)( - )
cos + cos = 2 cos (1/2)( + ) cos (1/2)( - )
cos - cos = -2 sin (1/2)( + ) sin (1/2)( - )
Certified ISO-9001:2000, BS EN 9002, ANSI/ASQC Q9002