【单选题】My roommate Tony is very untidy. He has brown hair and blue eyes. He leaves his laundry on the floor. When he cooks, he never washes the dishes. For a while, he had a bicycle on his bed. It is not sur...
A.
He has brown hair and blue eyes.
B.
He leaves his laundry on the floor.
C.
When he cooks, he never washes the dishes.
D.
For a while, he had a bicycle on his bed.
E.
It is not surprising that Tony can never find anything.
【简答题】已知向量 a 与 b 的夹角为60°,| b |=4,( a +2 b )?( a -3 b )=-72,求向量 a 的模.
【单选题】向量 a 的模为4,向量 b =( 0 , 2 ) ,若 ( a + b )⊥ b ,则向量 a 与 b 的夹角的大小是( )
【多选题】用户在选择商品化通用会计软件时,应着重考查会计软件的方面有( )。
【单选题】若向量 a 与 b 的夹角为60°, | b |=4,( a +2 b ).( a -3 b )=-72 ,则向量 a 的模为( )
【简答题】若向量 a , b 的夹角是60°, | b |=4 , ( a +2 b ) ? ( a -3 b )=-72 ,则向量 a 的模是 ______.
【多选题】用户在选择商品化通用会计软件时,应着重考察的方面有()。