Basics
sin(a) = 1 / cosec(a)
cos(a) = 1 / sec(a)
tan(a) = 1 / cot(a)
cot(a) = 1 / tan(a)
sin2(a) + cos2(a) = 1
tan2(a) + 1 = sec2(a)
cot2(a) + 1 = cosec2(a)
Addition Formulas
sin(a+b) = sin(a)cos(b) + cos(a)sin(b)
sin(a-b) = sin(a)cos(b) - cos(a)sin(b)
cos(a+b) = cos(a)cos(b) - sin(a)sin(b)
cos(a-b) = cos(a)cos(b) + sin(a)sin(b)
Half Angle
Double Angle
Law of Sines
Law of Cosines
