(HP-67) Barkers's Equation

[Albert Chan]

To complete the symmetry (again, assume sign(0)=1):

c² - 2W c + 1 = 0   → c = W ± √(W²-1)

c = cot(csc^-1(W)/2) = W + sign(W) √(W²-1)

Note: domain of csc^-1(W) = sin^-1(1/W) is |W| ≥ 1, otherwise c is a complex root.