搜题请搜索小程序“爱下问搜题”
问题 选择题
等比数列{an}中，若a1+a2=6，a2+a3=3，则a3+a4+a5+a6=（　　）
A．
15
8
B．
9
8
C．
9
4
D．
3
8
答案

由a2+a3=q（a1+a2）=6q=3，∴q=

1
2
，∴a3+a4+a5+a6=（a1+a2）（q2+q4）=
15
8
，

故选A．

单项选择题

关于客观资料的记录，正确的是

A．每天排尿4～5次，量中等

B．咳嗽剧烈，有大量黏痰

C．每天饮开水5次，每次约200ml

D．每餐主食2碗，一日3餐

E．发热2天，午后明显
查看答案
单项选择题

Estimating schedule activity costs involves developing an（）of the costs of the resources needed to complete each schedule activity. Cost estimating includes identifying and considering various costing alternatives. For example, in most application areas, additional work during a design phase is widely held to have the potential for reducing the cost of the execution phase and product operations. The cost estimating process considers whether the expected savings can offset the cost of the additional design work. Cost estimates are generally expressed in units of（）to facilitate comparisons both within and across projects.The（）describes the business need, justification, requirements, and current boundaries for the project. It provides important information about project requirements that is considered during cost estimating.

Cost estimates are generally expressed in units of（）to facilitate comparisons both within and across projects.

A．project scope statement

B．statement of work

C．project management plan

D．project policy
查看答案