ldcf.net
当前位置:首页 >> 1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45=? (算式... >>

1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45=? (算式...

1/55。 看分母 1,3,6,10,15,21,28,36,45, 逐次之差为2,3,4,5,6,7,8,9,。。。

楼主你好,你的这个问题非常的深奥,一般人是无法解答的,那么现在就由我来告诉你怎么在百度知道里提问题,希望楼主认真学习,仔细研究。谢谢: 1.你们家要有电; 2.你们家要有电脑; 3.还有有鼠标和键盘; 4.先接好电源; 5.然后打开电脑; 6....

分母都变成96,分子相加

通项为2/(n+1)(n+2)=2(1/(n+1)-1/(n+2))前n项和s=1-2/(n+2)故原式为4/5

1,3,6,10,15,21,28,36 规律第N个数等于从1加到N 1=1 3=1+2 6=1+2+3 10=1+2+3+4 …… X=(N+1)*N/2 0,1,3,6,10,15,21 规律第N个数等于从0加到N-1 0=0(N-1=0) 1=0+1(N-1=1) 3=0+1+2(N-1=2) 6=0+1+2+3(N-1=3) X=(N-1)*N/2

1/3+1/6+1/10+1/15+1/21+1/28 =5/15+1/15+1/6+1/10+1/21+1/28 =(5+1)/15+1/6+1/10+1/21+1/28 =6/15+1/6+1/10+1/21+1/28 =2/5+1/10+1/6+1/21+1/28 =4/10+1/10+1/6+1/21+1/28 =(4+1)/10+1/6+1/21+1/28 =5/10+1/6+1/21+1/28 =1/2+1/6+1/21+1/28 =3/...

1、数列求和的常用方法有:利用等差数列、等比数列的求和公式求和;分组求和;倒序相加;错位减法;裂项法。 2、本题中an=n(n+1)/2=(n²+n)/2,适宜用分组求和的方法求和。 3、解:因为1²+2²+3²+...+n²=n(n+1)(2n+1)/6...

1/3+1/15+1/35+1/63 =1/3+1/(3×5)+1/(5×7)+1/(7×9) =1/3+1/2×(1/3-1/5)+1/2×(1/5-1/7)+1/2×(1/7-1/9) =1/3+1/2×1/3-1/2×1/9 =1/3+1/6-1/18 =4/9

1/12=1/15+1/130+1/208+1/240 1/12=1/15+1/132+1/210+1/231 1/12=1/15+1/133+1/210+1/228 1/12=1/15+1/141+1/188+1/235 1/12=1/15+1/143+1/195+1/220 1/12=1/15+1/144+1/180+1/240 1/12=1/15+1/147+1/196+1/210 1/12=1/15+1/148+1/185+1/222 1/1...

1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45 =2*(1/6+1/12+1/20+1/30+1/42+...+1/90) =2*(1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+...+1/9*10) =2*(1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+...+1/9-1/10) =2*(1/2-1/10) =2*2/5 =4/5

网站首页 | 网站地图
All rights reserved Powered by www.ldcf.net
copyright ©right 2010-2021。
内容来自网络,如有侵犯请联系客服。zhit325@qq.com