Key points are not available for this paper at this time.
The estimate of third Hankel determinant H₃, ₁ (f) =|a₁\;a₂\;a₃\₂\;a₃\;a₄\₃\;a₄\;a₅| of the analytic function f (z) =z+a2z²+a3z³+, for which (1+zf^{} (z) /f^ (z) ) >-1/2 are investigated. The corrected version of a known results 2, Theorem 3. 1 and Theorem 3. 3 are also obtained.
Bansal et al. (Sun,) studied this question.