Trig Identities Flashcards
1
Q
Pythagorean identities
A
sin^2θ + cos^2θ = 1
tan^2θ +1 = sec^2θ
1 + cot^2θ = csc^2θ
2
Q
tan(A+-B) =
A
tanA+-tanB / 1+-tanAtanB
3
Q
sin2θ =
A
2sinθcosθ
4
Q
cos2θ =
A
cos^2θ - sin^2θ
OR
2cos^2θ - 1
OR
1-2sin^2θ
5
Q
tan2θ =
A
2tanθ / (1 - tan^2θ)
6
Q
tanθ =
A
sinθ / cosθ
7
Q
cotθ =
A
1 / tanθ
8
Q
cscθ =
A
1 / sinθ
9
Q
secθ =
A
1 / cosθ
10
Q
What trig functions are even or odd?
A
sin and tan are odd
cos is even
11
Q
cos (A+-B) =
A
cosAcosB-+sinAsinB
12
Q
sin(A+-B) =
A
sinAcosB+-cosAsinB
