Trig Identities Flashcards
1
Q
sin(A±B)
A
sinAcosB±cosAsinB
2
Q
cos(A±B)
A
cosAcosB∓sinAsinB
3
Q
tan(A±B)
A
tanA±tanB÷(1∓tanAtanB)
4
Q
tanθ
A
sinθ÷cosθ
5
Q
cotθ
A
cosθ÷sinθ
1÷tanθ
6
Q
secθ
A
1÷cosθ
7
Q
cosecθ
A
1÷sinθ
8
Q
sin²θ+cos²θ
A
1
9
Q
tan²θ+1
A
sec²θ
10
Q
cot²θ+1
A
cosec²θ
11
Q
sin2θ
A
2sinθcosθ
12
Q
cos2θ
A
cos²θ-sin²θ
2cos²θ-1
1-2sin²θ
13
Q
tan2θ
A
2tanθ÷(1-tan²θ)
14
Q
sinAcosB
A
½(sin(A+B)+sin(A-B))
15
Q
cosAsinB
A
½(sin(A+B)-sin(A-B))
16
Q
sinAsinB
A
½(cos(A-B)-cos(A+B))
17
Q
sinA+sinB
A
2sin(½A+½B)×cos(½A-½B)
18
Q
sinA-sinB
A
2cos(½A+½B)×sin(½A-½B)
19
Q
cosA+cosB
A
2cos(½A+½B)×cos(½A-½B)
20
Q
cosA-cosB
A
-2sin(½A+½B)×sin(½A-½B)
