A.
B.
C.
D.
[单选题]A.B.C.D.
[单选题]A.10.4mB.6.28mC.21.7mD.4.68m
[单选题]A.xyB.2xyC.D.xy+1
[单选题]A.振幅为1,初相为πB.振幅为7,初相为4/3πC.振幅为7,初相为7/6πD.振幅为1,初相为1/6π
[单选题]A.36N·sB.90N·sC.64N·sD.81N·s