Sin 2x
2 Sin x . Cos x
Cos 2x
Cos^2x - Sin^2x, 2 Cos^2x-1, 1-2 sin^2x
Tan 2x
2 Tan^2x / 1 - Tan x
Sin x + Sin y
2 Sin [ x+y/2 ] Cos [ x-y/2 ]
Cos x + Cos y
2 Cos [ x+y/2 ] Cos [ x-y/2 ]
Cos x - Cos y
-2 Sin [ x+y/2 ] Sin [ x-y/2 ]
Sin^-1 [-x]
-Sin^-1 [x]
Tan^-1 [-x]
-Tan^-1 [x]
Cosec^-1 [-x]
-Cosec^-1 [x]
Cos^-1 [-x]
Pi - Cos^-1 [x]
Sec^-1 [-x]
Pi - Sec^-1 [x]
Cot^-1 [-x]
Pi - Cot^-1 [x]