Harmonic function of a ninth chord?

A ninth chord is a type of extended chord that includes the root, third, fifth, seventh, and ninth degrees of a scale. In harmonic terms, it can be represented as a dominant ninth chord (e.g., C9) or a major ninth chord (e.g., Cmaj9), depending on the quality of the seventh (minor for dominant, major for major). The harmonic function of a ninth chord typically serves to create tension that resolves to a tonic chord, particularly in jazz and blues contexts. It enriches harmonic progressions by adding color and complexity to the sound.