Identity

Identity (Equation or Inequality)

An equation which is true regardless of what values are substituted for any variables (if there are any variables at all).

 

Identities:

1 + 1 = 2 (x + y)2 = x2 + 2xy + y2 a2 ≥ 0 sin2 θ + cos2 θ = 1

 

See also

Conditional equation, conditional inequality, trig identities