题目

设f(x)=10x+lgx,则f′(1)等于(    ) A.10                                                     B.10ln10+C.+ln10                                      D.11ln10 答案：解析：∵f′(x)=10xln10+lge,∴f′（1）=10ln10+lge=10ln10+.答案：B

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