【单选题】在轴的两端用两短V形块进行定位,限制了工件的 ( B)自由度。
【简答题】已知三角形 ABC 的三个顶点分别是 A ( 1/2,2 ), B ( -3,4 ), C(2 , 6), 求 BC 边上的中线 AD 的长
【单选题】Which of the following areas is NOT discussed in the passage?
B.
Nature of future work.
D.
Schools and libraries.
【单选题】已知三角形ABC三个顶点的坐标分别为A(0,0),B(3,4),C(4,3),判断三角形是否为直角三角形()
【简答题】There is no evidence ______ oil price will come down in the near future. A) which B) that C) where D) as
【单选题】The future of developing countries__________ the hands of children, which is __________education and training for young people is important.
【简答题】已知等腰三角形ABC的两个顶点分别是A(0,1)、B(0,3),第三个顶点C在x轴的正 半轴上.关于y轴对称的抛物线y=ax 2 +bx+c经过A、D(3,-2)、P三点,且点P关于直线AC的对称点在x轴上. (1)求直线BC的解析式; (2)求抛物线y=ax 2 +bx+c的解析式及点P的坐标; (3)设M是y轴上的一个动点,求PM+CM的取值范围.