1/(5*8)+1/(8*11)+1/(11*14)+L+1/(98*101)
=(1/5-1/8+1/8-1/11+1/11-1/14+.+1/98-1/101)*1/3
=(1/5-1/101)*1/3
=32/505
L的意思是按照前面的规律,省略记录补全
1/(5*8)+1/(8*11)+1/(11*14)+L+1/(98*101)
=(1/5-1/8+1/8-1/11+1/11-1/14+.+1/98-1/101)*1/3
=(1/5-1/101)*1/3
=32/505
L的意思是按照前面的规律,省略记录补全