Trig Identities Flashcards
Memorize each
1
Q
sinΘ
A
1/cscΘ
2
Q
cosΘ
A
1/secΘ
3
Q
tanΘ
A
1/cotΘ or sinΘ/cosΘ
4
Q
cscΘ
A
1/sinΘ
5
Q
secΘ
A
1/cosΘ
6
Q
cotΘ
A
1/tanΘ or cosΘ/sinΘ
7
Q
sin(-Θ)
A
-sinΘ
8
Q
cos(-Θ)
A
cosΘ
9
Q
tan(-Θ)
A
-tanΘ
10
Q
csc(-Θ)
A
-cscΘ
11
Q
sec(-Θ)
A
secΘ
12
Q
cot(-Θ)
A
-cotΘ
13
Q
sin^2Θ + cos^2Θ =
A
1
14
Q
1 + tan^2Θ =
A
sec^2Θ
15
Q
1 + cot^2Θ =
A
csc^2Θ
16
Q
cos2Θ
A
cos^2Θ-sinΘ^2
2cos^2Θ-1
1-2sin^2
17
Q
tan2Θ
A
(2tanΘ)/(1-tan^2Θ)
18
Q
sin2Θ
A
2sinΘcosΘ
19
Q
sin^2Θ
A
(1-cos^2Θ)/2
20
Q
sin(Θ/2)
A
+/- sqrt((1-cosΘ)/2)
21
Q
cos^2Θ
A
(1+cos2Θ)/2
22
Q
cos(Θ/2)
A
+/-sqrt((1+cosΘ)/2)
23
Q
tan(Θ/2)
A
+/-sqrt((1-cosΘ)/(1+cosΘ))
