APPLICATIONS OF CERTAIN FUNCTIONS ASSOCIATED WITH LEMNISCATE BERNOULLI

Abstract: For J(α; f(z)) = (1 − α) zf f( ′z (z )) + α [1 + zf f ′ ′′ (z (z )) ] (α ≥ 0), denote SL(α) and SLc as classes of α-convex and convex functions which respectively satisfy conditions | [J(α; f(z))]2 − 1| < 1 and [1 + zf f ′ ′′ (z (z )) ]2 − 1 < 1. Using established results, namely 1 + βzp′(z) ≺ 1+ 1+Dz Ez ; 1 + βzp p(′z()z) ≺ 1+ 1+Dz Ez and 1 + βzp p2( ′z (z )) ≺ 1+ 1+Dz Ez imply p(z) ≺ √1 + z where p(z) is an analytic function defined on the open unitdisk D with p(0) = 1. This article obtains conditions so that analytic functions f belong to the classes SL(α) and SLc.
Key words: Convex functions, differential subordination, lemniscate Bernoulli
Author: Suzeini Abdul Halim and Rashidah Omar
Journal Code: jpmatematikagg120017

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