sin^2 (x) + cos^2 (x) = ?
1
tan^2 (x) + 1
sec^2 (x)
sin(2x)
2 sin(x) cos(x)
cos(2x)
cos^2 (x) − sin^2 (x)
2cos^2(x) - 1
1 - 2sin^2(x)
(1-tan^2(x)) / (1+ tan^2(x))
sin(a + b)
sin(a) cos(b) + cos(a) sin(b)
cos(a + b)
cos(a) cos(b) − sin(a) sin(b)
Cot
1/tan = cos/sin
Sec
1/cos
Cosec
1/sin