trig identities Flashcards
1
Q
acute angles
A
always positive
2
Q
obtuse + reflex
A
use CAST to determine if +-
3
Q
sin^2x + cos^2x =
A
1
4
Q
tanx =
A
sinx
cosx
5
Q
cosec x =
A
1
sinx
6
Q
sec x =
A
1
cos x
7
Q
cot x =
A
1/tan x
sinx/cosx
8
Q
1 + tan^2x =
A
sec^2x
9
Q
1 + cot^2x =
A
cosec^2x
10
Q
cos 2x =
A
cos^2x - sin ^2x
1 - 2sin^2x
2cos^2x -1
11
Q
sin2x =
A
2sinx cosx
12
Q
tan2x =
A
2tanx
1-tan^2x
