Ai(z) and Ai'(z) have zeros on the negative real axis only. Bi(z) and Bi'(z) have zeros on the negative real axis and in the sector π/3< left bracketing bar arg z right bracketing bar <π/2. The nth (real) roots on the negative real axis of Ai(z), Ai'(z), Bi(z), and Bi'(z) are denoted a_n, a_n^, , b_n, and b_n^, , respectively (Abramowitz and Stegun 1972, p. 450; Fabijonas 2004; Fabijonas et al. 2004). Similarly, the nth complex root of Bi(z) and Bi'(z) in the sector π/3

Airy functions | root | zero