单选题已知x＞0，y＞0，点(x，y)在双曲线xy=2上移动，则的最小值为______．A．B．C．3D．2E．0
单选题已知-2x2+5x+c≥0的解为，则c为()．A．B．3C．D．-3E．
单选题5.2所示，弦长a＞b＞c，则它们所对应的圆周角()最大．(A)∠ABC(B)∠ACB(C)∠EDF(D)∠BAC(E)∠DFF
单选题设，其中与对角矩阵相似的有
单选题The trip was 40 miles. The speed for the first y miles was x, and the speed for the remaining trip was 1.2x. What is the average speed? (1)x=12 miles per hour (2)y=20 miles
单选题
单选题If r and s are integers and rs+r is odd, which of the following must be even? (A) r (B) s (C) r+s (D) rs-r (E) r2+s
单选题
单选题
单选题
单选题若a，b，c是△ABC的三边之长，则|a-b-c|+|b-c-a|-|c-a-b|=______
A.a+b-c
B.b+c-a
C.3a-b-C
D.3c-b-a
E.以上答案均不正确
单选题设m×n阶矩阵A的秩为n，则
单选题关于x的方程的解的个数为______个．
单选题三个边长为1的正方形拼成如图1所示的图形，图中有两条线段相交的锐角为α，tanα=______．图1A．B．C．D．1
单选题一元二次方程x2+bx+c2＝0有两个相等的实根，则( )．
单选题方程所表示的曲线是{{U}}{{/U}}．A.双曲线B.椭圆C.抛物线D.直线
单选题已知点C(2，一3)，M(1，2)，N(一1，一5)，则点C到直线MN的距离等于()．
单选题
单选题A short but heavy shower brought the ______ to a halt and everybody
went home.
A. procedure
B. process
C. proceedings
D. profession
单选题∫sin2xdx=______A．cos2x+CB．-cos2x+CC．cos2x+CD．cos2x+C