(1-1/2+1/3-1/4+……+1/19-1/20)/[1/(11×20)+1/(12×19)+……+1/(15×16)]=?
问题描述:
(1-1/2+1/3-1/4+……+1/19-1/20)/[1/(11×20)+1/(12×19)+……+1/(15×16)]=?
答
19
(1-1/2+1/3-1/4+……+1/19-1/20)/[1/(11×20)+1/(12×19)+……+1/(15×16)]=?
19