1/3+1/15+1/35+1/63+……+1/399+1/483
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/09/14 01:57:18
1/3+1/15+1/35+1/63+……+1/399+1/483
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
1.原式=1/(1x3)+1/(3x5)+1/(5x7)+1/(7x9)+1/(9x11)+1/(11x13)+1/(11*15)+1/(15*17)+1/(17*19)+1/(21*23)
=(1-2/3)+(2/3-3/5)+(3/5-4/7)+(4/7-5/9)+(5/9-6/11)+(6/11-7/13)+(7/13-9/15)+(9/15-11/17)+(11/17-13/19)+(13/19-15/21)+(15/21-17/23)
=1-17/23
=6/23
2.
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
=1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)+1/(6*7)+1/(7*8)+1/(8*9)+1/(9*10)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10
=1-1/10
=9/10
=(1-2/3)+(2/3-3/5)+(3/5-4/7)+(4/7-5/9)+(5/9-6/11)+(6/11-7/13)+(7/13-9/15)+(9/15-11/17)+(11/17-13/19)+(13/19-15/21)+(15/21-17/23)
=1-17/23
=6/23
2.
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
=1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)+1/(6*7)+1/(7*8)+1/(8*9)+1/(9*10)
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10
=1-1/10
=9/10
1/3+1/15+1/35……+1/399
1/3+1/15+1/35+.+1/399+1/483 怎么做
1/3+1/15+1/35+1/63+……+1/9999=?
计算1/3+1/15+1/35+1/63+1/99+1/143+1/195+255+1/323+1/399
1/3 + 1/15 + 1/35 + …… + 1/9999
1又1/3+3又1/15+5又1/35+……+19又1/399=?(要有过程)
1/3+1/15+1/35+1/63+1/99+1/143+1/195+1/255 +1/323+1/399=
3,15,35,63,99… 1,1,5,13… 这两组数字的规律
1/1*2+1/2*3+1/3*4+…+1/1993*1994 1/3+1/15+1/35+1/63+...+1/17*
1/3+1/15+1/35+…1/9999=?
1/3+1/15+1/35+1/63+1/99
1\3+1\15+1\35+1\63+1\99