(1-½²)(1-⅓²)(1-¼²)……(1-1/n²)(n是正整数)

问题描述:

(1-½²)(1-⅓²)(1-¼²)……(1-1/n²)(n是正整数)

(1-½²)(1-⅓²)(1-¼²)……(1-1/n²)
=(1-1/2)(1+1/2)(1-1/3)(1+1/3)(1-1/4)(1+1/4)....(1-1/n)(1+1/n)
=1/2*3/2*2/3*4/3*3/4*...(n-1)/n*(n+1)/n
=(n+1)/(2n)

(1-½²)(1-⅓²)(1-¼²)……(1-1/n²)(n是正整数)=(1-1/2)(1+1/2)(1-1/3)(1+1/3)(1-1/4)(1+1/4).(1-1/n)(1+1/n)=(1/2×3/2)(2/3×4/3).(n-1)/n (n+1)/n( 真分数和...