doyoustudyforatest

数学四边形的一道练习题.在四边形ABCD中,AB=DC,AD＜BC.求证：四边形ABCD是等腰梯形.（写出证明过程）【画辅助线证AD//DC】 one old lady is going to leave her job and she wants to find a job as language teacher in china 翻 she is going to 什么 her job she wants to be a volunteer in China 已知cosαcos（α+β）+sinαsin（α+β）=--3/5,β是第二象限角,则tan2β= She is going to( next year)括号里提问 八年级科学上册总复习题`1 急``只需要科学啲``其他不用``谢谢``1科学上册1-4单元模拟试卷`1 八年级上册科学A本是(浙教版的) 其中22-24页(复习题)答案!如果选择题与填空题带些解析(比较难的),那我就再给30分我不是直接抄的，而是我写完后想对下答案，因为我科学学得不好 八年级科学上第一章A本复习题的答案 八年级上册科学作业本复习题题目是什么我要的是题目不是答案……是八年级上册科学作业本水的利用和保护后面的复习题第29题,答案是P=833千帕,因P＞P0,所以,该车对路面的压强超过规定值. 八年级数学下册平行四边形证明题如图,平行四边形ABCD中,点E、F分别是边AB、DC的中点,求证﹕EF＝BC 八年级数学下册矩形的证明题目（有关平行四边形）如图,O是菱形ABCD的对角线交点,DE∥AC,CE∥BD.求证OCED是矩形 八年级下学期数学平行四边形证明题这些题都要最正确的证明步骤,行行好~\(≧▽≦)/~（要红框框中所有证明题哦） Now that she is out of a job,Lucy has been considering going back to school,but she hasn'tdecided yet.翻译, ___ she is out of a job.Lucy has beenconsidering going back to school,but she hasn’t decided yet.A since B as C now that A 是我后加上去的 正确答案是CCCCCCCCCCCCCCCCCCCC！ Now that she is out of a job ,Lucy __going back to scool,but she hasn't decided yet .Ahad comsideredB has been condering C con sidered D is going to consider 为什么选B You may not like lucy,but you have to ____that she's good at her job.A.damage B.admit C.prove D.explain now that she is out of job,lucy___going back to school,but she hasn't decided yethad considered has been considering为什么 设等差数列{an},{bn}的前n项和分别是Sn,Tn,且Sn/Tn=7n+2/n+3求a7/b7有助于回答者给出准确的答案 两个等差数列{an}和{bn}的前n项和分别为Sn和Tn,若Sn/Tn=(7n+1)/(4n+27),则a7/b7= 设等差数列{an}与{bn}的前n项之和为Sn,S`n,Sn/S`n=7n+2/n+3,求a7/b7 等差数列｛an｝.｛bn｝的前n项和分别为Sn.Tn.若Sn/Tn=(2n+2)/(n+3),则a7/b7= 等差数列An与Bn的前n项和分别是Sn和Tn,Sn/Tn=(7n+3)/(n+3),求A7/B7 He's seldom late for school,_____?— No.He is used to going to school early.[ ] A.isn't he B.He's seldom late for school,ia he — No.He is used to going to school early.[ ]为什么用 is uesd to 改错I'm going to late for school 八年级数学下册平行四边形 W: Mike, wake up1 It is time to go to school. Hurry up or you’re going to be late!M: Don’t worry. I can sleep all day long. Did you forget today is Martin Luther King’s birthday?Q: Who is the woman most likely to be?上面放不下 这句话 平行四边形 现规定一种新运算：a※b=ab+a-b,则1※（－2）= 若两个等差数列{An}和{Bn}的前n项和分别是Sn、Tn,已知Sn/Tn=7n/(n+3),则a5/a6=这是高一的数列题、、、、、网上有差不多的,但不一样,请不要随便引用哦、 已知等差数列an中 a5＝9 a2+a6＝14 若bn＝an+2∧n 求bn的前n项和sn 特殊的平行四边形 几何题如图,在△ABC中,D是BC边上的一点,E是AD的中点,过点A作BC的平行线交CE的延长线于点F,且AF=BD,连接BF.（1）求证：BD=CD；（2）如果AB=AC,试判断四边形AFBD的形状,并证明你的 任何一个系统,必须把它同所处的环境分开的"分界线",但这种界线往往是模糊.