题目:
81的平方根是
A.3
B.±3
C.-9
D.±9
答案:
答案:D
题目分析:解:∵(±9)2=81,∴81的平方根是±9.故答案为:±9.选D
点评: 此类试题属于基础性试题,考生解答此类试题时一定要注意分析平方根的定义和性质定理
81的平方根是
A.3
B.±3
C.-9
D.±9
答案:D
题目分析:解:∵(±9)2=81,∴81的平方根是±9.故答案为:±9.选D
点评: 此类试题属于基础性试题,考生解答此类试题时一定要注意分析平方根的定义和性质定理
(2011•抚顺)涵涵的爸爸买了一双有按摩功能的拖鞋,涵涵发现与脚接触的鞋底表面有许多小凸起,感觉很好奇,他穿上这双拖鞋后感觉脚底有点疼,由此他猜想压力的作用效果可能与 有关.为了验证他的猜想,涵涵找来了如图所示的实验器材:两个同样大小但疏密程度不同的钉板(质量不等),两个相同的海绵.请你帮他完成以下实验过程.
(1)由于钉板质量不同,所以聪明的涵涵把两个钉板的钉尖朝上放在水平桌面上,然后把两个相同的海绵分别放在两个 上观察两个海绵的形变程度.
(2)在实验中涵涵观察到,海绵形变较小,实验效果不明显,这时他发现桌上有几盒酸奶,于是他在两个 上分别放上质量 (填“相同”或“不同”)的酸奶,使实验效果变得明显了.
(3)实验中涵涵观察到,钉子较少时海绵的形变程度明显,由此可得到的结论是:当 一定时, 压力的作用效果越明显.
Tykoon is an online website that allows you to teach your child financial principles through allowances,assignment of tasks and daily chores.As the parent,you can assign a cash value to the things you want your child to do.Then,your child can go in,accept the task and add to their wish list of what they would like to purchase with the money that they earn. Let’s start with the parent side of things.The parent must be the one to set up the account.You simply enter your information and your child’s information to get started.You are then able to assign allowance amounts to your child. Then you can add tasks for your child to accept and link them to either their weekly allowance or a predetermined amount.Your child is then able to accept or decline their tasks.They can see how much each task earns,how often they need to do it and what they will get if they do!They can add items that they are working toward earning and can even earn nncash incentives such as extra TV time or staying up late! Tykoon is a great way to start teaching your child about responsibility and financial principles in fun and safe way.Through the creation of their own profile and the ability to accept or decline tasks,they are taught the skills that they will need later in life when they are managing their own budgets!So,head over and sign up for a free account today and watch your child get excited about doing their chores! And right now,as a special reward,if you share Tykoon with your friends and have five friends sign up and stay active for more than a month,you’ll earn a $25 Amazon.com gift card!So get your child enrolled(注册),tell your friends and let’s start teaching all our kids about the important financial principles today! 小题1:The purpose of the text is to________.
小题3:What can kids learn from Tykoon?
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下列关于异步传输模式ATM技术的叙述中,哪一条是不正确的
A.ATM技术可以满足用户对数据传输的服务质量的要求
B.ATM是B-ISDN选择的数据传输技术
C.ATM技术的实时性好,但灵活性不够
D.采用ATM技术可满足网络中突发性的通信量
患者,男,40岁,既往支气管哮喘病史5年,突发气短、喘息、呼吸困难,肺部听诊双肺可闻及广泛的哮鸣音,呼吸音延长。临床诊断为支气管哮喘急性发作。 可单独使用的哮喘控制药物为()
A.沙丁胺醇
B.特布他林
C.氨茶碱
D.孟鲁司特
E.福莫特罗
机房机架安装垂直度偏差应不大于()。
A.2mm
B.3mm
C.4mm
D.5mm