Common Trigonometric Identities PRESENTED BY: GROUP 5 WHAT IS IDENTITY WHEN IT COMES TO MATH In mathematics, an "identity" is an equation which is always true. These can be "trivially" true, like "x = x" or usefully true, such as the Pythagorean Theorem's "a2 + b2 = c2" for right triangles QUOTIENT IDENTITIES RECIPROCAL IDENTITIES CO FUNCTION IDENTITIES PYTHAGOREAN IDENTITIES PARITY IDENTITIES(EVEN ODD) PARITY IDENTITIES(EVEN ODD)