21．（12分）已知函数 $f(x)=x-1-a \ln x$ ．
（1）若 $f(x) \geq 0$ ，求 $a$ 的值；
②设 $m$ 为整数，且对于任意正整数 $n, ~\left(1+\frac{1}{2}\right)\left(1+\frac{1}{2^{2}}\right) \ldots\left(1+\frac{1}{2^{n}}\right)<m$ ，求 m 的最小值。
切线放缩 · 历年高考数学真题与解析
本页汇总 高考真题检索 的「切线放缩」高考数学真题共 1 道，覆盖 2017 年，最常出题型为 解答题；含完整答案与解析。
1questions
Past questions included
2017
Years covered
区分题为主
Overall difficulty
Free-response
Most common question type
Practice This Topic
Do 5 reliable past questions first, then see the answers and explanations after you submit
Core competencies应用
Past Question List
相关考点
所属章节
Keep Practicing This Topic
Start from one question and continue with the same question type, knowledge point, and approach. You can also describe this topic in one sentence to build a practice paper or handout and print it.
View all past questions for this topic 用这个考点出一份练习 Paper出一份讲义（例题 + 练习）