On Subclass of Bazilevi•c Function B1(®), It's Distortion and the Fekete-SzegÄo Problem

Abstract: In this paper we present the distortion and the Fekete-SzegÄo problem of subclass of Bazilevi·c functions, B1(®). First, we present the result of Singh concerning the sharp value of the coe±cients for B1(®), ja2j, ja3j and ja4j. Second, we give a solution of the Fekete-SzegÄo problem, i.e. an estimate of ja3 ¡ ¹a 2 2j for any real and complex numbers ¹ where a2 and a3 are the coe±cients of functions f in B1(®), where B1(®) is de¯ned by (2), i.e. for each ® > 0 and for z 2 D, Re f 0 (z) f(z) z ®¡1 > 0. These results are sharp for the functions f0 de¯ned by (3) for any real number ¹ which satis¯es ¹ < (1 ¡ ®)=2, or ¹ ¸ (4 + 3® + ® )=[2(2 + ®)] and for any complex number ¹ which satis¯es j3 + ® ¡ 2¹(2 + ®)j ¸ (1 + ®) 2 . These results are sharp for the functions f1 de¯ned by (4) for the other real and complex numbers ¹. Next, we use similar methods to get estimates for linear expressions involving higher coe±cients of function in B1(®). 2
Penulis: Marjono
Kode Jurnal: jpmatematikadd060009

Artikel Terkait :

Jp Matematika dd 2006