trig identities & double angle Flashcards
1
Q
sin(2x)=
A
sin(2x)= 2sin(x)cos(x)
2
Q
cos(2x)=
A
cos(2x)
=cos ²x - sin ²x
=2cos ²x-1
=1-2sin ²x
3
Q
tan2x
A
tan2x= 2tanx/1-tan ²x
4
Q
secx
A
1/cosx
5
Q
cosecx
A
1/sinx
6
Q
cotx
A
1/tanx
7
Q
sec^2x
A
1+tan^2x
8
Q
cosec^2x
A
1+cot^2x
9
Q
cos^2x =. (use for integration)
A
1/2(1+cos2x)
10
Q
sin^2x =. (use for integration)
A
1/2(1-cos2x)
