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cos (A - B)
cos A cos B + sin A sin B
cos (A + B)
cos A cos B - sin A sin B
sin (A + B)
sin A cos B + cos A sin B
sin (A - B)
sin A cos B - cos A sin B
sin 2x
2 sin x cos x
cos 2x (1)
1 - 2 sinĀ² x
cos 2x (2)
cosĀ² x - sinĀ² x
cos 2x (3)
2 cosĀ²x - 1
tan (A + B)
(tan A + tan B) / (1 - tan A tan B)
tan (A - B)
(tan A - tan B) / (1 + tan A tan B)
tan 2x
2 tan x / (1 - tanĀ² x)
Pythagorean Identities
sinĀ² x + cosĀ² x = 1
1 + tanĀ² x = secĀ² x,
1 + cotĀ² x = cscĀ² x.