1/2=1-1/2,1/6=1/2-1/3,1/12=1/3-1/4...请根据以上的规律计算:1/6+1/12+1/20+1/30+1/42
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1/2=1-1/2,1/6=1/2-1/3,1/12=1/3-1/4...请根据以上的规律计算:1/6+1/12+1/20+1/30+1/42
1/6+1/12+1/20+1/30+1/42
=(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1/2-(1/3-1/3)-(1/4-1/4)-(1/5-1/5)-(1/6-1/6)-1/7
=1/2-0-0-0-0-1/7
=5/14
1/6+1/12+1/20+1/30+1/42
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1/2-1/7
=7/14-2/14
=5/14
1/6+1/12+1/20+1/30+1/42
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6+1/7
=(1/2-1/7)
=5/14
1/6+1/12+1/20+1/30+1/42
=1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)+1/(6*7)
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1/2-1/7
=5/14
不懂可追问
满意请采纳
谢谢
原式=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1/2-1/7
=5/14
1*1/2=?
1+1=2?
1+1=2?
1+1×2=?
2-1=1
2+1+2+6=
Sn=1/(2^2-1)+1/(4^2-1)+1/(6^2-1)+.+1/[(2n)^2-1]求和
1+2+1+2+1+2+1+2+1+2+1+2+1+2 =( )*( ) =()
巧算:(1+1/2+1/3+1/4+1/5)*(1/2+1/3+1/4+1/5+1/6)-(1+1/2+1/3+1/4+1/5+1/6)*(1/2+1/3+1/4+1/5)(1+1/2+1/3+1/4+1/5)*(1/2+1/3+1/4+1/5+1/6)-(1+1/2+1/3+1/4+1/5+1/6)*(1/2+1/3+1/4+1/5)=====
(1-1/2)+(1-1/6)+(1-1/12)+...+(1-1/110)=?
1-1/2+1/3-1/4+1/5-1/6+1/7.-1/50=?
1/2+1/6+1/12+...+1/56=快
1/2+1/6+1/12+1/20=
1+1/2+1/6+1/16=?
1/2+1/6+1/12+…+1/1560=?
1*2*3+1-1+1/6=?
已知1/2=1-1/2,1/6=1/2-1/3,请计算1/2-1/6-1/12-1/20...-1/132
1-1/2+1/3-1/4+1/5-1/6+…+1/15=23*[1/( )+1/( )+1/( )+1/( )]