المستخلص: |
Let 𝒜0 denotes the class of analytic functions defined by (𝑧) = 𝑧 + Σ 𝑎𝑛 ∞ 𝑛= 2 𝑧𝑛 and 𝑧 belongs to the open unit disk 𝕌 = {𝑧: |𝑧| < 1}. The sharp bound is obtained for the coefficient functional |𝑎3 − 𝜇𝑎2 2 |, where 𝜇 ∈ ℂ or ℝ and 𝑎2, 𝑎3 are respectively the second and the third coefficient for 𝑓 belonging to a certain subclass ℛ𝛼, 𝛽 (𝜆, 𝜌) defined by a fractional operator. By specializing the parameters 𝛼, 𝛽, 𝜆 and 𝜌, many consequence results are obtained. Further, an improvement for the estimation of |𝑎3 − 𝜇𝑎2 2 | is investigated by dividing the intervals of 𝜇 ∈ ℝ . In addition, sharp estimates for the first few coefficients of the inverse functions of ℛ𝛼, 𝛽 (𝜆, 𝜌) are derived.
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