On generalizations of two theorems of Leindler
Wei Bao-rong · Journal of Zhejiang University(Science Edition) · 2009
Let g(x)∶=sum from n=1 to ∞ bn sin nx,and {bn}∈NBVS.By applying the inequality En(g,p)≤‖g-Sn(g)‖Lp and the properties of NBVS,the relations between the best approximation of g(x) and its Fourier coefficients under the L2πp norm are given.