Abstract
For 0 < α ≤ 1, analytic functions f(z) = z + a2z2 + a3z3 + … in the unit disk U are strongly starlike of order α if ¦arg {zf′ (z)/f(z)}¦ < πα / 2, z ∈ U. We find sharp estimates on the fourth and fifth coefficients of functions in this class.
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Ali, R.M., Singh, V. On the fourth and fifth coefficients of strongly starlike functions. Results. Math. 29, 197–202 (1996). https://doi.org/10.1007/BF03322218
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DOI: https://doi.org/10.1007/BF03322218