Level 480 Level 482
Level 481

### Double- & Half-Angle Formulas

#### 28 words 0 ignored

Ready to learn       Ready to review

## Ignore words

Check the boxes below to ignore/unignore words, then click save at the bottom. Ignored words will never appear in any learning session.

Ignore?
sin2α=
2sinαcosα
1 - 2sin²α
cos2α= (in terms of sine)
2cos²α - 1
cos2α= (in terms of cosine)
cos²α - sin²α
cos2α= (in terms of cosine and sine)
tan2α=
2tanα/(1 - tan²α)
sin(α/2)=
±√[(1 - cosα)/2]
cos(α/2)=
±√[(1 + cosα)/2]
tan(α/2)=
(1 - cosα)/sinα
tan(α/2)
sinα/(1 + cosα)=
Sin (2θ)
2 Sinθ Cosθ
Cos (2θ)
Cos²θ - Sin²θ
Tan (2θ)
2 Tanθ / 1 - Tan²θ
Sin (θ/2)
±√1 - Cosθ / 2
Cos (θ/2)
±√1 + Cosθ / 2
Tan (θ/2)
±√1 - Cosθ / 1 + Cosθ
sin(2x)
2sinxcosx
cos(2x)
cos²x-sin²x
cos(2x)
2cos²x-1
cos(2x)
1-sin²x
tan(2x)
2tanx/1-tan²x
sin(½x)
+-√(1-cosx/2)
cos(½x)
+-√(1+cosx/2)
tan(½x)
(1-cosx)/sinx
tan(½x)
sinx/1+cosx
sin(x)sin(y)
½[cos(x-y)-cos(x+y)]
cos(x)cos(y)
½[cos(x-y)+cos(x+y)]
sin(x)cos(y)
½[sin(x+y)+sin(x-y)]
cos(x)sin(y)
½[sin(x+y)-sin(x-y)]