已知等差数列{an}满足,则它的前10项和S10=( )
记数列的前项和为,且,则 ()
已知向量,向量,且,则实数x等于( )
复数 = A B C D
定义,若,则( )
Suppose the least distance fron poinrs of the xurve(曲线)to the y-axis is then the velue of a is