1⼀1×4+1⼀4×7+1⼀7×10+1⼀10×13+···+1⼀2008×2011 =

2025-06-22 23:25:12
推荐回答(1个)
回答1:

解:1/(1×4)+1/(4×7)+1/(7×10)+1/(10×13)+···+1/(2008×2011)
=(1-1/4)/3+(1/4-1/7)/3+...+(1/2008-1/2011)/3
=(1-1/4+1/4-1/7+...+1/2008-1/2011)/3
=(1-1/2011)/3
=670/2011

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