Trig Identities Flashcards
1
Q
Sin(A+B)
A
SinaACosB + CosASinB
2
Q
Sin(A-B)
A
SinACosB - SinBCosA
3
Q
Cos(A+B)
A
CosACosB-SinASinB
4
Q
Cos(A-B)
A
CosACosB+SinASinB
5
Q
Tan(A+B)
A
TanA + TanB / 1-TanATanB
6
Q
Tan(A-B)
A
TanA - TanB / 1+TanATanB
7
Q
Cot(A+B)
A
CotBCota-1 / CotB + CotA
8
Q
Cot(A-B)
A
CotBCota+1 / CotB - CotA
9
Q
Sin(A+B) Sin(A-B)
A
Sin^2A - Sin^2B
10
Q
Cos(A+B) Cos(A-B)
A
Cos^2A-Sins^2B
11
Q
2SinA CosB
A
Sin(A+B) + Sin(A-B)
12
Q
2CosA SinB
A
Sin(A+B) - Sin(A-B)
13
Q
2SinA CosB
A
Sin(A+B) - Cos(A-B)
14
Q
2CosA CosB
A
Cos(A+B) + Cos(A+B)
15
Q
Sin C + Sin D
A
2 Sin(C+D/2) Cos(C-D/2)
16
Q
Sin C - Sin D
A
2 Cos(C+D/2) Sin(C-D/2)
17
Q
Cos C + Cos D
A
2 Cos(C+D/2) Cos(C-D/2)
18
Q
Cos C - Cos D
A
-2 Sin(C+D/2) Cos(C-D/2)
19
Q
Sin 2θ
A
2SinθCosθ
20
Q
Cos 2θ
A
Cos^2 θ - Sin^2 θ
21
Q
1 + Cos 2θ
A
2Cos^2θ
22
Q
1 - Cos 2θ
A
2Sin^2θ
23
Q
Tan 2θ
A
2tanθ / 1-tan^2θ
24
Q
Sin3θ
A
3Sinθ - 4Sin^3θ
25
Q
Cos 3θ
A
4Cos^3θ - 3Cosθ
