【简答题】若直线l的方向向量为(4,2,m),平面α的法向量为(2,1,-1),且l⊥α,则m=______.
【单选题】What is the difference between velocity and speed?
A.
There is no difference.
B.
Velocity is a vector, and speed is a scalar.
C.
Speed is a vector, and velocity is a scalar.
D.
Speed states only a magnitude, and velocity states a magnitude and direction.
E.
Velocity states only a magnitude, and speed states a magnitude and direction.
【单选题】atención, tengo algo que decirte.
【判断题】胚胎在原肠胚形成中,细胞有多种运动形式。
【单选题】What is the difference between velocity and speed?
A.
There is no difference, they are both vectors.
B.
Speed is a scalar and velocity is a vector.
C.
Speed is a vector and velocity is a scalar.
D.
There is no difference, they are both scalars.
【简答题】已知l∥α,且l的方向向量为u=(2,m,1),平面α的法向量为v=(1, ,2),则m=____.
【简答题】若l的方向向量为(2,1,m),平面α的法向量为(1, 1 2 ,2),且l⊥α,则m=______.
【单选题】新产品、 新型设备及生产工艺 引入应 采用的验证类型是
【单选题】双极型晶体管和场效应晶体管的控制信号为( )。