雄县顺丰快递电话:1/4+1/12+1/24+1/40+……+1/19800=?

来源：百度文库编辑：杭州交通信息网时间：2024/05/06 12:10:48

解:1/4+1/12+1/24+1/40+……+1/19800
=(1/2)*[1/2+1/6+1/12+1/20+...+1/9900]
=(1/2)*[1/1*2+1/2*3+1/3*4+1/4*5+...+1/99*100]
=(1/2)*[1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+...+1/99-1/100]
=(1/2)*[1-1/100]
=(1/2)*(99/100)
=99/200

原式=1/4*[1/1+1/（1+2）+1/（1+2+3）……+1/（1+2+3+……+99）]

“1/1/2+2/1/6+3/1/12+4/1/12+......20/1/420”怎么简算？ 1/4+1/12+1/24+1/40+……+1/19800=? 7/12=1/？+1/？+1/？ 4/9，1，4/3，（），12，36 1/1+1/2+1/3+1/4+。。。。+1/N 是多少 5/12×1/7+1/7÷4/5怎么简便计算？齐齐算 1/(10/1+12/1) 一:1／8＝1/( )+1/( )二:1/10=1/( )+1/( )三:1/12=1/( )+1/( )+1/( ) 1/11+1/12+1/13+1/14+1/15 1/2+1/6+1/12+1/20+1/30