2是什么意思

某椭圆方程为x^2-y^2/9=1,该方程是否问为椭圆的标准方程?x^2下面的分母1要不要写上去? 当x=2009,y=2010时,代数式(x-y/x)除于[x-(2xy-y的平方)/x]的值是多少 ①已知x=2009,y=2010,求代数式x-y/x÷（x-（2xy-y^2/x))的值②先化简,再求值：（a^2-b^2/a^2-ab）÷（a+（2ab+b^2/a)当b=-1时,再从-2＜a＜2的范围内选取一个合适的整数a代入求值大家帮帮忙啊~~~~~~~~急啊~~~~~~~ 设非零复数x,y满足x^2+xy+y^2=0.则代数式[x/(x+y)]^2010-[y/(x+y)]^2010=? 已知函数f（x）=Asin（wx+φ）周期为π 且图像上的一个最低点（2π/3 ,-2） 求解析式和当x∈（0 π/12）当x∈（0 π/12）时f（x）的最值略带些步骤 已知椭圆 x^2/ a^2 + y^2/ b^2=1（a,b大于0的两个焦点分别为F1（-c,0）,F2 (c,0)(C大于0)过E(a^2/c,0)的直线与椭圆相交于A,B两点,且F1A平行于F2B,F1A=2F2B设Q(c,1),P为椭圆上动点,若PQ+ 根号3倍PF2的最小值为4,求 已知椭圆C1:x2/a2+y2/b2=1的左右两焦点为F1,F2,离心率为1/2,抛物线C2：y2=4mx（m＞0）与椭圆C1有公共焦点F2（1,0）,求椭圆和抛物线方程. 计算题,关于根号计算3√3-（√2-√3）+√2=请竖式排列 高中数学椭圆的几何性质部分焦点在x轴上,则长轴长就是x轴上两端点之间的距离,那如果焦点在y轴上,那长轴长是x轴上两端点之间的距离,还是y轴上两端点之间的距离?书上没说清楚,望大师赐 已知函数f(x=Asin(wx+fai),的图像如图(其中A>0,w>0,|fai| 分解因式中的分组分解法.请多给一些例题 赛车的外侧和内侧车轮的距离是2米,当赛车绕圆形跑道跑一圈时,外侧车轮比内侧车轮多走多远?注：不要r、π、b,要数字快 已知函数f(x)=Asin(ωx+φ)(A>0,ω>0,|φ| 已知函数f(x)=Asin(ωx+φ)(A>0,ω>0,|φ| 当焦点在x轴时,椭圆的标准方程是：x^2/a^2+y^2/b^2=1,(a>b>0)； 当焦点在y轴时,椭圆的标准方程是：y^2/a^2+x^2/b^2=1,(a>b>0)；2个方程当中的a,b是表示长轴和短轴还是长半轴和短半轴 The USA lies on the other side of—— A Pacific B Pacific Ocean C The Pacific D the Ocean Pacific今天这是第几次蛋疼了. 赛车的外侧与内侧车轮相距两米,当赛车绕圆形跑道跑一圈时,外则车轮比内侧多走了多远?我知道是2*2*π=12.56,但怎么来的呀,不然明天老师hold不住要K我了重赏 The United States of America is in the n ___ The United States of America is in the n ___part of America.It has an area of 9,372,256square k ___.Its c ___is Washington D.C.It has f___states.It has a p___ of 266,578,000.Its native l___is English,with 首字母填空 The d.of America is very important in history Which state of America is in the Pacific Ocean?Which country is to the north of the America? 根据首字母填空 It is reported that t___ of people were killed or injurd in the hurricane in AmericaThough the high school entrance exam is coming ,you should r___ yourselfChina held the 2008 Olypic Games s_____She p___ walking to the factory t los Angeles/America/west/in/of/the/is连词成句 已知函数f(x)=Asin(ωx+φ),x∈R(之中A>0,ω>0,0 已知函数f(x)=Asin(wx+b)+k,x∈R(其中A>0,W>0,0 已知函数F(X)=Asin(ωx+ψ)(其中A>0,ω>0,0 函数f(x)=Asin(ωx+Φ)+b的部分图像如图,则S=f(0)+f(1)+f(2)+...+f(2011)= The British Isles＿＿of a group of islands that lies off the west coast of Europe .为什么选is consisted呢?这是我们期中考试的卷子。而且答案就是is consisted没错！ The British Isles are a group of islands that lies off the west coast of Europe是什么意思 The British Isles is a group of islands that lies ________ the west coast of Europe.(Unit5-8)A.in?B.on?C.from?D.off为什么选D不选其它?其它选项用在这里又是什么意思呢?请分析一下英语中关于方位的相关语法. x-(0.4x-33)+143=(1+0.15)x 1.4X*0.8=X+15 X=多少?快