Radians
Sine and also cosine are cofeatures and also complements 


Tangent and cotangent are coattributes and also complements 


Secant and also cosecant are cofeatures and complements 


Degree
Sine and also cosine are cofeatures and also complements  sin(90°  x) = cos x  cos(90°  x) = sin x 
Tangent and also cotangent are cofeatures and also complements  tan(90°  x) = cot x  cot(90°  x) = tan x 
Secant and cosecant are cofeatures and also complements  sec(90°  x) = csc x  csc(90°  x) = sec x 
Degree Example:
sin A = cos B = A = B = cos(90°  A) = sin AUsing substitution:cos(90°  67.4°) = sin 67.5°cos(22.6°) = sin(67.5)° As such, the worth of cosine B is equal to sine A which is the cofunction and also match of B. The process remains the very same whether you are in level mode or radian mode.Let"s view just how this deserve to be used.Use the coattribute identities to evaluate the expression without a calculator! sin2 (23°) + sin2 (67°)Step 1: Note that 23° + 67° = 90° (complementary)Tip 2: usage the coattribute identity and let x = 23°sin(90°  x) = cos x
therefore sin(67°) = cos(23°)
Tip 3: use substitution sin2(23°) + cos2(23°)
Tip 4: use the Pythagorean identity sin2θ + cos2θ = 1sin2(23°) + cos2(23°) = 1
Thus, sin2(23°) + sin2(67°) = sin2(23°) + cos2(23°) = 1
Related Links:Math Trigonomeattempt Sum and Difference of Angles IdentitiesTrigonometric Identities  Reciprocal Identities 
To attach to this Cofunction Identities page, copy the complying with code to your site: