$
TV + INTERNET DUO
59
/MONTH
FOR 3
MONTHS
+
FREE
TIVO® DVR
LEARN MORE
FOR 12 MONTHS
Certain conditions apply.
www.mathwords.com
about mathwords
website feedback
Search
index: click on a letter
A
B
C
D
E
F
G H
I
J
K
L M N O
P
Q
U
V W X Y
Z
A to Z index
R
S
T
index: subject areas
numbers & symbols
sets, logic, proofs
geometry
Trig Identities
Identities involving trig functions are listed below.
Pythagorean Identities
Reciprocal Identities
Ratio Identities
sin2 θ + cos2 θ = 1
tan2 θ + 1 = sec2 θ
cot2 θ + 1 = csc2 θ
algebra
trigonometry
advanced algebra
& pre-calculus
Odd/Even Identities
calculus
advanced topics
probability &
statistics
real world
applications
sin (–x) = –sin x
csc (–x) = –csc x
cos (–x) = cos x
sec (–x) = sec x
tan (–x) = –tan x cot (–x) = –cot x
multimedia
entries
Cofunction Identities, radians
Cofunction Identities, degrees
sin (90° – x) = cos x cos (90° – x) = sin x
tan (90° – x) = cot x cot (90° – x) = tan x
sec (90° – x) = csc x csc (90° – x) = sec x
Periodicity Identities, radians
sin (x + 2π) = sin x
csc (x + 2π) = csc x
Periodicity Identities, degrees
sin (x + 360°) = sin x
csc (x + 360°) = csc x
cos (x + 2π) = cos x sec (x + 2π) = sec x
cos (x + 360°) = cos x sec (x + 360°) = sec x
tan (x + π) = tan x
tan (x + 180°) = tan x cot (x + 180°) = cot x
cot (x + π) = cot x
Sum/Difference Identities
Double Angle Identities
Half Angle Identities
or
or
or
Product to Sum Identities
or
Sum to Product Identities
See also
Sine, cosine, tangent, cosecant, secant, cotangent
this page updated 21-feb-16
Mathwords: Terms and Formulas from Algebra I to Calculus
written, illustrated, and webmastered by Bruce Simmons