INITIAL COEFFICIENT BOUNDS ON A SUBCLASS OF BOUNDED TURNING FUNCTIONS Rcos ASSOCIATED WITH COSINE FUNCTION
Tsukuba Journal of Mathematics, cilt.49, sa.2, ss.167-180, 2025 (ESCI, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 49 Sayı: 2
- Basım Tarihi: 2025
- Doi Numarası: 10.21099/tkbjm/20254902167
- Dergi Adı: Tsukuba Journal of Mathematics
- Derginin Tarandığı İndeksler: Emerging Sources Citation Index (ESCI), Scopus
- Sayfa Sayıları: ss.167-180
- Anahtar Kelimeler: Analytic functions, coe‰cient bounds, cosine function, Hankel determinant, subordination, successive coe‰cients di¤erence, Zalcman functional
- Bursa Uludağ Üniversitesi Adresli: Evet
Özet
In the present paper, we investigate some initial coe‰cient bounds on a subclass of bounded turning functions Rcos associated with cosine functions. Also, we obtain the initial coe‰cient bounds for the first five coe‰cients of the functions that belong to these subclass Rcos. Further, initial consecutive coe‰cients module di¤erence estimates for the subclass Rcos is studied. Moreover, we determine the upper bound of Zalcman functional for the subclass Rcos for the case n = 3, showing that the Zalcman conjecture holds for these values.