百度试题 结果1 题目 公式法(1)等差数列的前n项和公式:Sn=f(n(a1+an).2)=___f(n(n-1),2)___;(2)等比数列的前n项和公式:na,,g=1,Snai-ang1a(1-q),q≠1.1-q1-q 相关知识点: 试题来源: 解析 na1+ d 反馈 收藏
To me, SNA is a place that helps to nurture students growth in preparation for their next steps in life. The school provides great opportunities and cultivates ambitious free thinkers. SNA是一个帮助学生成长的地方,为学生人生的下一步做好充分准备。学校提供教师很多的提升自我的机会,...
网络分析方法中常见的分析方法包括复杂网络分析(Complex Network Analysis,CNA)、社交网络分析(Social Network Analysis,SNA)和生态网络分析(Ecological Network Analysis,ENA)。其中生态网络分析是基于网络理论,将生态系统中的生物群落和它们之间的相互关系...
关键词:无铅焊料;制备工艺;微观组织;力学性能 中图分类号:TN 604 文献标识码:A 文章编号:1001-3474(2010)01-0016-04 M icrostructure and Properties of Sn -Bi -Sb Lead -free Sol der W ANG Da -yong ,GU X iao -long (Zhejiang A sia General Sol d ering&BrazingM aterial CO .,LTD of...
1. Chua B, Desai SP, Tierney MJ et al (2013) Effect of microneedles shape on skin penetration and minimally invasive continuous glucose monitoring in vivo. Sens Actuat A Phys 203:373–381. https://doi.org/10.1016/j.s...
and problems of conic sections in PEP-A (China) and UCSMP (US) high school mathematics textbooks. The study examined similarities and differences in contextual features and mathematical connections in the textbook problems, and employed social net...