Trigonometric Identities Flashcards
1
Q
sin ø
A
Opposite / Hypotenuse
the “y” coordinate
2
Q
cos ø
A
Adjacant / Hypotenuse
the “x” coordinate
3
Q
tan ø
A
Opposite / Adjacant
sin ø / cos ø
y / x
4
Q
csc ø
A
Hypotenuse / Opposite
1 / sin ø
1 / y
5
Q
sec ø
A
Hypotenuse / Adjacent
1 / cos ø
1 / x
6
Q
cot ø
A
Adjacent / Opposite
cosø / sinø
x / y
7
Q
sin2ø + cos2ø =
A
1
8
Q
tan2ø +1 =
A
sec2ø
9
Q
cot2ø + 1 =
A
csc2ø
10
Q
sin(2ø)
A
2sin(ø)cos(ø)
11
Q
cos(2ø)
A
cos2ø - sin2ø
2cos2ø - 1
1 - 2sin2ø
12
Q
tan(2ø)
A
2tan ø / 1 - tan2ø
13
Q
Law of Sines
A
sina / A = sinb / B = sinc / C
14
Q
Law of Cosines
A
a2 = b2 + c2 - 2bc cos(a)
15
Q
Derivative of sin ø
A
f(ø) = sin ø
f’(ø) = cos ø