【简答题】圆x 2 +y 2 +2x-6y+5=0的圆心______半径______.
【单选题】大气的组成是由()
A.
78%的氮气,21%的氧气以及1%的其他气体组成
B.
75%的氮气,24%的氧气以及1%的其他气体组成
C.
78%的氮气,20%的氧气以及2%的其他气体组成
【简答题】与圆(x+3) 2 +y 2 =1及圆(x-3) 2 +y 2 =9都外切的圆的圆心轨迹方程为______.
【简答题】Matching words with definitions. Following are definitions of ten words. Clearly write each word next to its definition. a. pack b. household c. liberty d. block e. obvious f. cast ...
【简答题】求圆心在直线3x+4y-1=0上,且过两圆x 2 +y 2 -x+y-2=0与x 2 +y 2 =5交点的圆的方程.
【简答题】大气由________、________和________而组成。
【简答题】Match the words with their definitions. ( From Text8 匹配题, 答案请输入小写abcd,一道题输入一个答案) _______ 1. dedicate a. bring or call together into a group or whole _______2. devour b. a specific use...
【单选题】澳门的总面积因为沿岸填海造地而一直在扩大,目前已达()平方公里。
【简答题】e a. of or relating to an economy, economics, or finance economic theories