click below
click below
Normal Size Small Size show me how
Trig Identities 2
Sum, diff, product, power
| Term | Definition |
|---|---|
| sin(u±v) | sin u cos v ± cos u sin v |
| cos(u±v) | cos u cos v ±' sin u sin v |
| tan(u±v) | tan u ± tan v / 1 ±' tan u tan v |
| sin(2u) | 2 sin u cos u |
| cos(2u) | cos²u-sin²u or 2cos²u - 1 or 1-2sin²u |
| tan(2u) | 2 tan u / 1 - tan²u |
| sin²u | 1/2[1-cos(2u)] |
| cos²u | 1/2[1+cos(2u)] |
| tan²u | 1 - cos(2u) / 1 + cos(2u) |
| sin u + sin v | 2 sin (u+v/2) cos (u-v/2) |
| sin u - sin v | 2 cos (u+v/2) sin (u-v/2) |
| cos u + cos v | 2 cos (u+v/2) cos (u-v/2) |
| cos u - cos v | -2 sin (u+v/2) sin (u-v/2) |
| sin u sin v | 1/2 [cos(u-v) - cos(u+v)] |
| cos u cos v | 1/2[cos(u-v) + cos(u+v)] |
| sin u cos v | 1/2[sin(u+v) + sin (u-v)] |
| cos u sin v | 1/2[sin(u+v) - sin (u-v)] |
| sin (u/2) | sqrt (1-cosu / 2) |
| cos (u/2) | sqrt (1+cosu / 2) |
| tan (u/2) | (1-cosu)/sinu or sinu/(1+cosu) |