We continue the study of several related extremal problems for functions analytic in a simply connected domain G with a rectifiable Jordan boundary Γ. In particular, the problem of optimal recovery of a derivative at a point z₀ ∈ G from limit boundary values given with an error on a measurable part γ₁ of the boundary Γ for the class Q of functions with limit boundary values bounded by 1 on γ₀ = Γ γ₁ as well as the problem of the best approximation of the derivative at a point z₀ ∈ G by bounded linear functionals in L^∞(γ₁) on the class Q. Complete exact solutions of the considered problems are obtained.

中文翻译：

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从在边界的一部分上给出错误的函数的值中最佳解析函数的导数的恢复。II

我们继续研究具有可纠正约旦边界Γ的简单连接域G中的函数解析的几个相关极值问题。具体地，其衍生物的最佳恢复的在点问题Ž ₀ ∈ ģ具有错误上可测量的部分给定的γ从极限边界值₁该类的界面Γ的Q的功能与极限边界值由1上界γ ₀ =γγ ₁以及所述衍生物的在一个点的最佳近似的问题ž ₀ ∈ ģ通过界定在线性函大号^∞（γ ₁）在课堂Q上。获得了所考虑问题的完整准确的解决方案。