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二重积分问题,设非均质圆形薄板的半径为R,其上的面密度与到圆心的距离成正比,比例系数是k.以圆形薄板的圆心为原点建立直角坐标系,把圆板的质量m表示为二重积分为：. 二重积分的问题区域D：X^2+Y^2小于等于1 则 ∫∫xydσ=0 关于这点我有点疑问区域是个圆形,所以关于X轴 Y轴 同时也关于原点对称（1）对于关于X轴,Y轴对称有 f(x,-y) = f(-x,y) = -f(x,y) 所以f(x,y) 关于 二重积分相关问题实在对不住大家,我的低级失误把题目抄错了,这是正确的那个题,1这个简图是依据什么画出来的? 2为什么θ要分两种情况? 求二重积分的题目 火鸡用英语怎么说? 超级火鸡用英语怎么翻译 这顿饭的主菜是火鸡用英文翻译 书上是这样说的,1.带电粒子只要是垂直射入电场(不论正负)电场力一定做功但下一句却说:2.带电粒子只要是垂直射入电场,动能不一定变化"1中不是说电场力一定做功吗?但2却说"动能不一定变 Which of the following sentence is right?(1)Why didn't you borrow him the story-book?(2)Although I have got enough money for the watch,yet I wouldn't like to buy it.(3)The film has begun for half an hour.(4)Our hometown has taken place great changes which of the following sentences is Which of the following statesments is right?（ ）A:Did your mother home last night?B:Did you in last night?CWere you in last night?D:Were you stay at home last night?并说说为什么对,其他选项为什么不对?但希望会的， which of the following is right? 2、设复数z满足z(2-3i)=6+4i（其中i为虚数单位）,则z的模为（ ） 先把火鸡切成片翻译 英语翻译Do you need to put ____ ____ ____ this ____ pf turkey? 高数 一道题用万能代换求不定积分. 第二题不理解 详细说明 一道数学计算题 设集合M={1,2,zi},i为虚数单位,N=｛3,4｝,M∩N=｛4｝,则复数z= （ ） A.-2i B.2i C.-4i D.4i which of the following is NOT 若复数z满足（z-i）（i-1）=2+zi,i为虚数单位,求z Which of the following is NOT ture?的中文意思是什么? 若复数z满足1+zi=i(i是虚数单位),则z^2的值为?急 求不定积分时用三角代换时为什么不用考虑正负也不用加上绝对值符号.例如..根号下X^2-1用sec u带换时开根号的结果不用考虑正负 一笔画出一个正方形中间加个X号? Which of the following sentences is right?A.The school has been opened for 10 years B It is 10 years since they got married C There have had great changes in our town over the years Which one is right of the following sentences?A.I don't think it is a free choice.B.I think it is not a free choice.C.I didn't think it is a free choice.D.I thought it wasn't a free choice. Which of following sentences is right?A.Here Amy comes.B.Here comes she.C.here comgs Amy.D.Therecomes Amy. 求关于汉字与词语误解的例子现代汉语中有许多字的用法与愿意已不同了,如：出 与 重,射与 短.另外也有是词语改变的,如：牛高马大本来是牛大马高,山青水秀本来是山秀水清等.求更多类似 按例子,写出吃字组成的词语.理解准确透彻叫（ ）被人占了便宜叫( )受苦叫（ ）做事费力叫（ ）受了惊吓叫（ ） 中国养殖火鸡前景如何? 火鸡养殖的前途?