cofunction
Ninety-degree angle complement
A cofunction is a trigonometric function paired with another such that each equals the other when applied to complementary angles—angles that sum to 90 degrees.
Sine and cosine are cofunctions: the sine of 30° equals the cosine of 60°.
The "co-" in cosine, cotangent, and cosecant signals this complementary relationship.
Opposite over hypotenuse
- cosineRatio in triangle math
- tangentLine touching curve once
- cotangentTangent reciprocal function
- secantTrig ratio, 1/cos
cosecant · sin · cos · tan · cot · sec · complementary angle · identity
What makes complete
- counterpartCorresponding person or thing
- reciprocalShared between two parties
- dualHaving two parts
- correspondingMatching in character
Mutually supplying lacks
- proofDemonstration of truth
- formulaFixed method or notation
- relationshipConnection between entities
- equalitySame status for all
substitution · simplification · derivation · theorem · equation
sine
Opposite over hypotenuse
secant · cosecant · sin · cos · tan · cot · sec · complementary angle · identity · reciprocal
complement
What makes complete
- counterpartCorresponding person or thing
- reciprocalShared between two parties
- dualHaving two parts
corresponding · matched · symmetric · interdependence · relationship
complementary
Mutually supplying lacks
- proofDemonstration of truth
- formulaFixed method or notation
- relationshipConnection between entities
equality · substitution · simplification · derivation · theorem · equation