Trigonometric Identities and Rules Flashcards
1
Q
Cos2x in Double Angle Formula Expansion
A
1-sin^2 x
cos^2 x - sin^2 x
2cos^2 x - 1
2
Q
Sin2x in Double Angle Formula Expansion
A
2sinx2cosx
3
Q
Tan2x in Double Angle Formula Expansion
A
(2tanx)/(1-tan^2 x)
4
Q
Identity linking tan and sec
A
1 + tan^2 x = sec^2 x
5
Q
Identity linking cot and cosec
A
1 + cot^2 x = cosec^2 x
6
Q
Identity linking sin, cos and tan
A
sinθ/cosθ = tanθ
7
Q
Identity linking sin and cos
A
sin^2 θ + cos^2 θ = 1
8
Q
Arc length in radians
A
rθ
9
Q
Area of sector in radians
A
(θ/2)r^2
10
Q
Small angle approximation of sinθ
A
θ
11
Q
Small angle approximation of tanθ
A
θ
12
Q
Small angle approximation of cosθ
A
1-(θ^2/2)
13
Q
Reciprocal to Cosθ
A
Secθ
14
Q
Reciprocal to Sinθ
A
Cosecθ
15
Q
Reciprocal to Tanθ
A
Cotθ
16
Q
Repeat for Tan
A
add 180°
17
Q
Repeat for Sin
A
subtract from 180°
18
Q
Repeat Cos
A
Subtract from 360°
19
Q
d/dy(sinx)
A
cosx
20
Q
d/dy(-cosx)
A
-sinx
