ω = 2π T sin α 2= 소r 1 - cosα 2 cos α 2= 소r 1 + cosα 2 sin(-θ)

cos ↵ = sin
csc ↵ = sec
cot ↵ = tan
↵ & complimentary.
r
↵
1 cos ↵
sin = ±
⇥
2
2
r
↵
1 + cos ↵
cos = ±
2
2
sin2 ✓ + cos2 ✓ = 1
sin( ✓) = sin ✓
cos( ✓) = cos ✓
tan2 ✓ + 1 = sec2 ✓
tan( ✓) = tan ✓ 1 + cot2 ✓ = csc2 ✓
2
=
T
c 2 = a 2 + b2
a 2 = b2 + c 2
b2 = a 2 + c 2
sin
sin ⇥
=
a
b
2ab cos
2bc cos
2ac cos
sin ⇤
=
c
sin(↵ + ) = sin ↵ cos + cos ↵ sin
sin 2✓ = 2 sin ✓ cos ✓
sin(↵
) = sin ↵ cos
cos ↵ sin
cos 2✓ = cos2 ✓ sin2 ✓
cos(↵ + ) = cos ↵ cos
sin ↵ sin
cos 2✓ = 1 2 sin2 ✓
cos(↵
) = cos ↵ cos + sin ↵ sin
cos 2✓ = 2 cos2 ✓ 1
p
1 2
v·w
A
=
S(S
a)(S
b)(S
c)
A= r
cos =
2
v w
1
A = ab sin
s=r
2