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【多选题】
已知 X 为随机变量,且 E ( X ), D ( X ) 均存在,则下列式子成立的有A.
E[X-E(X)]=0
B.
E[E(X)]=E(X)
C.
D[E(X)]=0
D.
E[X+E(X)]=2E(X)
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