Trigonometry Identities Flashcards
1
Q
sinX/cosX ?
A
tanX
2
Q
1/sinX ?
A
cosecX
3
Q
1/secX ?
A
cosX
4
Q
1/tanX ?
A
cotX
5
Q
sin²X + cos²X ?
A
sin²X + cos²X = 1
6
Q
sec²X - tan²X ?
A
sec²X - tan²X = 1
7
Q
cosec²X - cot²X ?
A
cosec²X - cot²X = 1
8
Q
sin2x ?
A
2sinXcosX
9
Q
cos2x ?
A
cos²x - sin²x
10
Q
Relate cos2x with sin²x?
A
1 - 2sin²x
11
Q
Relate cos2x with 2cos²x
A
Cos2x = 2cos²x - 1
12
Q
Relate tan2x with tan²x
A
tan2x = 2tanx ÷ (1 - tan²x)
13
Q
What is sin(X) - sin(Y) ?
A
2cos( (X+Y)÷2) • sin( (X-Y)÷2)
14
Q
What is cos(X) + cos(Y) ?
A
2cos( (X+Y)÷2) • cos( (X-Y)÷2)
15
Q
What is cos(X) - cos(Y) ?
A
-2sin( (X+Y)÷2) • sin( (X-Y)÷2)