Trigonometric formula Flashcards
1
Q
Cos(a±b)
A
Cosa.Cosb∓Sina.Sinb
2
Q
Sin(a±b)
A
Sina.Cosb±Sinb.Cosa
3
Q
tan(a±b)
A
(tana±tanb)/(1∓tana.tanb)
4
Q
Sin2α
A
2SinαCosα
5
Q
Cos2α
A
Cos²α-Sin²α=1-2Sin²α=2Cos²α-1
6
Q
tan2α
A
2tanα/(1-tan²α)
7
Q
Sin3α
A
3Sinα-4Sin³α
8
Q
Cos3α
A
4Cos³α-3Cosα
9
Q
Cosa+Cosb
A
2Cos(a+b/2).Cos(a-b/2)
10
Q
Cosa-Cosb
A
-2Sin(a+b/2).Sin(a-b/2)
11
Q
Sina+Sinb
A
2Sin(a+b/2).Cos(a-b/2)
12
Q
Sina-Sinb
A
2Cos(a+b/2).Sin(a-b/2)
13
Q
Cosa.Cosb
A
½⌈Cos(a+b)+Cos(a-b)⌋
14
Q
Sina.Sinb
A
-½⌈Cos(a+b)-Cos(a-b)⌋
15
Q
Sina.Cosb
A
½⌈Sin(a+b)+Sin(a-b)⌋
