先举一个在教学中碰到的实例:“同学们在昨天的作业中有这样一个问题:用数学归纳法证明(n+1)(n+2)……(n+n)=2n·1·3……(2n-1)时,从k到k+1时等式左边要增乘的代数式是什么?同学们没有考虑到当n=k时,式子是从k+1开始到k+k结束的,当n=k+1时,式子是从k+2开始到(k+1)+(k+1)结束的。因此,等式左边要增乘的代数式是2(2k+1)”。我在分析完后稍 First give an example encountered in teaching: “Students in the homework yesterday there is such a problem: the use of mathematical induction proof (n +1) (n +2) ...... (n + n) = 2n · 1 ······················································································ What are the algebraic equations to be multiplied to the left of the equation from k to k + 1 when students do not consider that when n = k, the formula starts from k + 1 The formula ends from k + 2 to (k + 1) + (k + 1) when n = k + 1. Therefore, the algebra for multiplication on the left side of the equation is 2 ( 2k + 1) ”. I am slightly after analysis