1⼀1*4+1⼀4*7+1⼀7*10+1⼀10*13+1⼀13*16的简便计算方法(过程)

2025-02-27 12:39:45
推荐回答(1个)
回答1:

裂项法:
1/1*4+1/4*7+1/7*10+1/10*13+1/13*16
=1/3*(1-1/4+1/4-1/7+1/7-1/10+1/10-1/13+1/13-1/16)
=1/3*(1-1/16)
=1/3*15/16
=5/16