4× 10fenzhi3×7=12you2fenzhi1
来源:学生作业帮助网 编辑:作业帮 时间:2024/08/18 04:37:18
![4× 10fenzhi3×7=12you2fenzhi1](/uploads/image/f/327726-54-6.jpg?t=4%C3%97+10fenzhi3%C3%977%3D12you2fenzhi1)
原式=(1+3n+7)(n+3)/2=(3n²+17n+24)/2
1.原式=7/10×〖1+9〗=72.原式=2/3×18+4/9×18=12+8=203.未知4.〖2/7×7〗×3+〖1/3×3〗×7=6+7=13再问:第3题呢?
11/7*1/4+1/4÷7/10-1÷4=11/28+5/14-1/4=3/4-1/4=1/2
7/10(3/7+1)-1/4=1-1/4=3/4
1/1×4+1/4×7+1/7×10+1/10×13+1/13×16+1/16×19+1/19×22=1/3(1-1/4+1/4-1/7+1/7-1/10+1/10-1/13+1/13-1/16+1/
没看出来,分母是加在分子前加1吗?要是那样,即使后来乘2005*2008,也是0请断句
1/1*4=(1/3)*(1-1/4)1/4*7=(1/3)*(1/4-1/7)...1/91*94=(1/3)*(1/91-1/94)所以:1/1*4+1/4*7+1/7*10+1/10*14+.+
1/1*4+1/4*7+1/7*10+...+1/2005*2008+1/2008*2011=1/3(1-1/4)+1/3(1/4-1/7)+1/3(1/7-1/10)+.+1/3(1/2005-1/
有(3n+7-1)÷3+1=n+3个所以原式=(1+3n+7)(n+3)/2=(2n+4)(n+3)
1/(a*b)=(1/a-1/b)/(b-a)1/(1*4)=(1/1-¼)/(4-1)1/(4*7)=(¼-1/7)/(7-4).1/(100*103)=(1/100-1
答案如下,慢慢看.找出数列1,4,7,10...2008,2011的通项为3n-2(n=1,2,3...670)上式每一项的通项为:1/(3n-2)*(3n+1)1/(3n-2)*(3n+1)=1/3
1/2+3/4+7/8+...+1023/1024=1-1/2+1-3/4+.1-1/1024=10-(1/2+1/4+1/8+...+1/1024)=10-(1/2-1/1024*1/2)/(1-1
10/21×(5/6-1/4)=10/21×(20/24-6/24)=10/21×(14/24)=5/3×1/6=5/18.7/8×3/10+3/10×9/8=(7/8+9/8)×(3/10)=2×(
1/1*4=(1/3)*(1-1/4)1/4*7=(1/3)*(1/4-1/7)1/7*10=(1/3)*(1/7-1/10)1/1*4+1/4*7+1/7*10+.+1/52*55*+1/55*58
=1+150/(3*5)+150/(5*7)+150/(7*9)+150/(9*11)+150/(11*13)=1+75*(1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-
(1/4*1/7+1/7*1/10+1/10*1/13+1/13*1/16)*3=[(1/3)*(1/4-1/7)+(1/3)*(1/7-1/10)+(1/3)*(1/10-1/13)+(1/3)*(
2010-1-4-7-10-...-61-64=2010-(1+64)×22/2=2010-715=1295
依次是02/710/710不懂再问再答:别忘了评价~~O(∩_∩)O~~祝你开心
(-7.25)+(+7又1/4)=0(-36.35)+26.35+10=0
就最后一个有问题(8)(3又4/1)+(-1又12/1)=2又6/1还有你的写法有点问题不过在本子上写应该对在电脑上就错了``