Approximation of functions by (C,2)(E,1) product summability method of Fourier series

Jitendra Kumar Kushwaha


Various investigators such as Leindler [10], Chandra [1], Mishra et al. [7], Khan [11], Kushwaha [6] have determined the degree of approximation of  2 pai-periodic functions belonging to generalized Lipschitz class of functions through trigonometric Fourier approximation using different summability means.  Recently H.K. Nigam [12] has determined that the Fourier series is summable under the summability means (C,2)(E,1) but he did not find the degree of approximation of function belonging to various classes.  In  this paper a theorem concerning the degree of approximation of function  belonging to  class by (C,2)(E,1) product summability method of Fourier series  has been established which  in turn generalizes the result of  H.  K. Nigam [12].


Degree of approximation; Fourier series; Pruduct summability methods.

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