Unexpected things may happen every day but no one can tell when and where. People usually get surprised or frightened by such things. One day I __ 31__ a taxi to go to a meeting. As it came near the c
Although he knew little about the large amount of work done in the field , he succeeded other more well-informed experimenters failed. A．as B．unless C．w
.
代入得(b-
)2=a2+b2-ab,
.
=
=(a-1)+
+2≥
+2.
时，取“=”,即a=1+
时,b有最小值2+
.