It is used as a noun when denoting the angular part of the set of solutions to Laplace's equation in spherical coordinates.
This adjective's namesake number is specified by a sum that includes the EulerÂ–Mascheroni (mask-uh-ROH-nee)  constant. If the Laplacian of a real-valued function equals zero, then that function is named for this adjective. It is used as a noun when denoting the angular part of the set of solutions to Laplace's equation in spherical coordinates. This term names an expression whose divergence can famously be proven via a medieval method in which every term is compared to a smaller term that is a reciprocal of a power of two. This word's namesake (*)  analysis describes the mathematical modelling of overlapping waves, such as in music, where it describes small-integer note ratios. For 10 points, give this adjective used to describe the series "the summation, where  n  goes from one to infinity, of one-over- n ."
This adjective's namesake number is specified by a sum that includes the EulerÂ–Mascheroni (mask-uh-ROH-nee)  constant.
harmonic  [accept  harmonic  number or  harmonic  function or spherical  harmonics  or  harmonic series or  harmonic  analysis] 