Cot x is 1/tan x or cos x / sin x or +- sqrt cosec^2 x -1.
Original Cast Recording. Arista, 1973. Includes original hit song Day by Day sung by Robin Lamont. Sung by the original cast members David Haskell, Peggy Gordon, Robin Lamont, Gilmer McCormick, Sonia Manzano, Jeffrey Mylett, Stephen Nathan, Herbie Braha, Joanne Jonas, and Lamar Alford.
. One Day at a Time  was recorded by Gloria who released it as a single in August 1977. The song originally peaked at No.5, before being re-released a year later.