,则
等于( )。A.1
B.-1
C.2
D.
[单选题]设,则等于( )。A.1B.-1C.2D.
[单选题]设,则等于( )。A.1B.-1C.2D.
[单选题]设,则等于( )。A.1B.-1C.2D.
[单选题]设,则等于( )。A.1B.-1C.2D.
[单选题]设,则等于( )。A.1B.-1C.2D.
[单选题]设,则等于( )。A.1B.-1C.2D.
[单选题]设,则等于( )。A.1B.-1C.2D.
[单选题]设,则等于( )。A.1B.-1C.2D.
[单选题]设,则等于( )。A.1B.-1C.2D.
[单选题]设,则等于( )。A.1B.-1C.2D.