Trig Identities Flashcards
1
Q
sin^2(x) + cos^2(x)
A
1
2
Q
tan^2(x) + 1
A
sec^2(x)
3
Q
sin^2(x)
A
(1-cos2x) / 2
4
Q
cos^2(x)
A
(1+cos2x) / 2
5
Q
sin(2x)
A
2sin(x)cos(x)
6
Q
sin(x)cos(x)
A
1/2 * sin(2x)
7
Q
sin(sx)cos(tx)
A
1/2 [sin(s + t)x + sin(s - t)x]
8
Q
sin(sx)sin(tx)
A
-1/2 [cos(s + t)x - cos(s - t)x]
9
Q
cos(sx)cos(tx)
A
1/2 [cos(s + t)x + cos(s - t)x]
