Trig Identities Flashcards
1
Q
sin A cos B =
A
1/2 (sin(A − B) + sin(A + B))
2
Q
sin A sin B =
A
1/2 (cos(A − B) − cos(A + B))
3
Q
cos A cos B =
A
1/2 (cos(A − B) + cos(A + B))
4
Q
sin^2 x + cos^2 x =
A
1
5
Q
tan^2 x + 1 =
A
sec^2 x
6
Q
cos^2 x =
A
1/2 (1 + cos 2x)
7
Q
sin^2 x =
A
1/2 (1 − cos 2x)
8
Q
sin 2x =
A
2 sin x cos x
9
Q
cos 2x =
A
cos^2 x − sin^2 x
10
Q
sin A cos B =
A
1/2 (sin(A − B) + sin(A + B))
11
Q
sin A sin B =
A
1/2 (cos(A − B) − cos(A + B))
12
Q
cos A cos B =
A
1/2 (cos(A − B) + cos(A + B))
13
Q
sin(A + B) =
A
sin A cos B + cos A sin B
14
Q
cos(A + B) =
A
cos A cos B − sin A sin B
