Trig Identities Flashcards
1
Q
sin2(x) double angle
A
2sin(x)cos(x)
2
Q
tan2(x) double angle
A
(2tan(x))/(1-tan^2(x))
3
Q
cos2(x) double angle
A
cos^(x)-sin^2(x) = 2cos^2(x)-1 = 1-2sin^2(x)
4
Q
sin^2(x) half angle
A
(1-cos2(x))
5
Q
cos^2(x) half angle
A
(1+cos2(x))/2
6
Q
tan^2(x) half angle
A
(1-cos(x))/sin(x) = sin(x)/(1+cos(x))
7
Q
sin(x)
A
opp/hyp
8
Q
cos(x)
A
adj/hyp
9
Q
tan(x)
A
opp/adj = sin(x)/cos(x)
10
Q
csc(x)
A
hyp/opp = 1/sin(x)
11
Q
sec(x)
A
hyp/adj = 1/cos(x)
12
Q
cot(x)
A
adj/opp = cos(x)/sin(x) = 1/tan(x)
13
Q
sin(-x)
A
-sin(x) odd
14
Q
cos(-x)
A
cos(x) even
15
Q
tan(-x)
A
-tan(x) odd
