“…A function f ∈ A is said to be bi-univalent in D if both f and f −1 are univalent in D. Let Σ denote the class of bi-univalent functions in D given by (1.1). Various subclasses of Σ were introduced and non-sharp estimates on the first two coefficients |a 2 | and |a 3 | in the Taylor-Maclaurin series expansion (1.1) were found in several recent investigations (see, for example, [1,2,3,6,7,8,13,21,22,23,24,30,31,32,33,34,35,36,37,38] and references therein). However, the problem is to find the coefficient bounds on |a n | (n = 3, 4, .…”