EXWisthepricetermwiththegreatestresponsibilityofth

2x^2+x x^3+2x^2+2x+1=0的解法 above loyalty to the people I was born 如图(1)(2)(3),AC∥BD,动点P在平面上一点.（1）当动点P在如图（1）的位置时,求证：∠APB=∠PAC+∠PBD（2）当动点P在如图（2）（3）的位置时,试探索∠APB与∠PAC、∠PBD的关系 如图,已知△ABC为正三角形,EC⊥平面ABC,BD⊥平面ABC已知△ABC为正三角形,EC⊥平面ABC,BD⊥平面ABC,且EC、DB在平面ABC的同侧,M为EA的中点,CE=CA=2BD,求证：（1）DE=DA（2）平面BDM⊥平面ECA 英语翻译：大家都知道,他天生一副好嗓子（be gifted with) be born.翻译成汉语是什么 cos²(-a)-sin(-a)/ tan(2π+a)化简 化简：sin²（α+π)cos(-α+π)/tan(α+π)tan(α+2π)cos²(-α-π)1.cos（27°+α）cos（33°-α）-sin（27°+α）sin（33°-α） 2.sin²（α+π)cos(-α+π)/tan(α+π)tan(α+2π)cos²(-α-π) The flowers are very beautiful.改为感叹句 求函数y=logcosx(tanx+1)的定义域 （cosx为底） 2sinα*cosα*cos(2π-α)+cos(π+2α)*cosα*tanα化简! （2sin²α+2sinα*cosα)/（1+tanα） 的值如何进行化简只需要化简成sinα和cosα的形式就可以了 解分式方程的基本思路是把分式方程化为_____,由于在分式方程的两边乘了一个可能使分母为_____的整式所以方程必须检验 立体几何:长方体ABCD-A'B'C'D'中,求证A'C'‖平面ABCD 如图所示宇宙飞船发动机内氢气和氧气燃烧生成水的微观过程.下列说法中错误的为什么是水分子是由氢分子,氧分子构成的 已知ABCD-A'B'C'D'为长方体,对角线AC'与平面A’BD相交于点G,则G是三角形A'BD的A 垂心 B 重心 C 外心 D 内心 答案选B 请附上过程!谢谢!已知空间三条直线中，任何两条不共面，且两两垂直，若直 立体几何问题 四棱锥F-ABCD的底面ABCD是菱形四棱锥F-ABCD的底面ABCD是菱形,对角线AC=2,BD=√2,AE,CF都与平面ABCD垂直,AE=2,CF=2.:(1)求二面角B-AF-D的大小（2）求四棱锥E-ABCD与四棱锥F-ABCD公共部分体积安 717.宇宙飞船上的造氧机,其原理是靠电解水产生氧气和氢气吗? 立体几何 已知长方体ABCD-A'B'C'D',求证:AB//平面CDA'B'已知长方体ABCD-A'B'C'D',求证:AB//平面CDA'B'急等!怎么证? 改错There have had great changes in Jiangsu.My bike is the same as you.Please bring the umbrella with you.It is raining outside.I believe there will not be a heavy snow tonight. Is there a shoe store near here?(改为陈述句） 1x2分之1+2x3分之1+3x4分之1+···+x(x+1)分之1=12分之1解方程 请问 ：The man knocked at the door."the door"是宾语吗?这个句子中knocked at the door 是谓语,还是knocked at 是谓语,the door 做宾语 The policeman came up to the lonely house with door ___,____ there..The policeman came up to the lonely house with door ___,____ there for a while and then entered it.a.open; to stand b.opening; stoodc.open; stood d.opened; standing选C 第一个为 是knocked at the door还是knocked on the door 考试一题,there used to be a park,_______? 我填wasn't there,错了,说是didn't there我不知道为什么用didn't,我的思路是there be,反义是be there的格式,哪位高手能解释下为什么是didn't而不是wasn't. there used to be a coffee shop next to you r house,--------?a:wasn't there b:wasn't it ; 为什么不选B? There was a knock at the door.It was the second time someone______me that evening.(2 分)A.interruptedB.had interruptedC.would interruptD.interrupt There___many old and low huoses near our school A.used to have B.used to be 这里为什么选B?used to have 应该怎么用? 2.The new library__B___now was designed by a famous designer from France.A.has been built B.being built为什么不能选 英语翻译还有the one that gives the most water for the least money.怎么译? 已知抛物线经过点A（-1,0）,B(0,-3),C(3,0)三点则抛物线的解析式是