A.1
B.-1
C.k
D.1k
[单选题]已知xy=kz(k为正常数),则等于( )。A.1B.-1C.kD.1k
[单选题]已知xy=kz(k为正常数),则等于( )。A.1B.-1C.kD.1k
[单选题]已知xy=kz(k为正常数),则等于( )。A.1B.-1C.kD.1k
[单选题]已知xy=kz(k为正常数),则等于( )。A.1B.-1C.kD.1k
[单选题]已知xy=kz(k为正常数),则等于( )。A.1B.-1C.kD.1/k
[单选题]已知xy=kz(k为正常数),则等于( )。A.1B.-1C.kD.1k
[单选题]已知平面简谐波的方程为,式中A、B、C为正常数,此波的波长和波速分别为( )。A.,B.,C.,D.,
[单选题]已知为某函数的全微分,则a等于( )。A.-1B.0C.1D.2
[单选题]已知级数是收敛的,则下列结论成立的是( )。A.必收敛B.未必收敛C.D.发散
[单选题]等于( )。A.B.C.D.