Fundamental Identities

In this lesson, we will revisit the reciprocal identities, the quotient identities, and the Pythagorean identities. We will learn about the negative-angle identities. Together, these identities form the "fundamental identities". We will use the fundamental identities to find missing trigonometric function values given one value and the quadrant. Additionally, we will learn how to write one trigonometric function in terms of another.