A:Not only ... but also
B:Both ... or
C:Both ... and
D:Either ... or
已知m是方程x2-x-2=0的一个根,则m2-m的值是( )
已知两个向量a→=(1+log2x,log2x),b→=(log2x,1)
(1)若a→⊥b→,求实数x的值;
(2)求函数f(x)=a→•b→,x∈14,2的值域.
注意:1)词数100左右;
2)开头结尾已写好,但不计入总词数;
3)可以适当增加细节,以使行文连贯。
Dear Sri/Madam,
I read your advertisement in the newspaper and
Yours,
Li Hua