Third Hankel determinant for the inverse of reciprocal of bounded turning functions has a positive real part of order alpha
B. Venkateswarlu, Neha Rani ยท Ufimskii Matematicheskii Zhurnal ยท 2017
Let ๐ ๐ be the class of functions ๐ (๐ง) univalent in the unit disk ๐ธ = ๐ง : |๐ง| 0, ๐ง โ ๐ธ, and ๐ป 3 (1) be the third Hankel determinant for inverse function to ๐ (๐ง).In this paper we obtain, first an upper bound for the second Hankel determinant, |๐ก 2 ๐ก 3 -๐ก 4 |, and the best possible upper bound for the third Hankel determinant ๐ป3(1) for the functions in the class of inverse of reciprocal of bounded turning functions having a positive real part of order alpha.