Conversions between Radians and Degrees
67.5 degrees
3π/8
sec = 1/cos
Reciporcal
sin 330
-1/2
cos x = 4/5
sin x =√3/2
60, 120
225 degrees
5π/4
sin x/2 = +- √1-cosx/2
Half Angle
tan 225
1
tan x = 12/5
sin x = 12/13
tan x = 1
45, 225
12π/4
540 degrees
cos (x+-y) = cosx cosy-+sinx siny
Sum & Difference
cos 135
-√2/2
cos x = 4/5
tan x = 3/4
cos x = √2/2
45, 315
214π/3
12,840 degrees
cos2x = 1-sin2x
Double Angle
sin 120
√3/2
csc x = 13/5
sin x = 5/13
sin x =1/2
30, 150
714 degrees
119π/30
cos(-A) = cos A
Opposite Angle
cot 45
√2
cot x = 12/8
sec x = 17/12
cos x = √3/2
30, 330