Jackson算子关于二阶连续模的最佳逼近常数

The Constant of Optimal Approximation of the Jackson Operator on the Second Order Modulus of Continuity

求了用Jackson算子Jn（f.,x）逼近函数f（x）（∈C2n）时关于二阶连续模的最佳逼近常数：及用阶数不超过n的三角多项式H对连续函数f（x）的最佳逼近En（f）,的上界估计：

In this paper we obtain the constant of optimal approximation of the Jackson operator Jn (f;x) on the second order modulus of Cntinuity ω2 (f; ) of the function function f(x)( C2π),i.e where the constant 8- is est possible.