(1-1/2²)×(1-1/3²)×···×(1-1/9²)×(1-1/10²)
问题描述：
(1-1/2²)×(1-1/3²)×···×(1-1/9²)×(1-1/10²)
答
1-1/n^2=(n^2-1)/n^2=(n-1)(n+1)/n^2=(n-1)/n * (n+1)/n如：(1-1/2²)=1/2 * 3/2(1-1/3²)=2/3 * 4/3(1-1/9²)=8/9 *10/9(1-1/10²)=9/10 * 11/10可知中间项都消去了,只剩了1/2 与 11/10所以结果为1...