【单选题】在等差数列{ a n }中,已知 a 1 + a 2 + a 3 + a 4 + a 5 =20,那么 a 3 = ( )
【判断题】Let him come in and fill our home with wealth!让他进来把我们家装满爱。
【简答题】请每人文字总结(该家具绘制体会,100字左右)并上传一件传统明清家具的CAD图纸。
【单选题】在等差数列 中,已知 ,那么 等于( ).
【单选题】在等差数列{an}中,已知a5+a8=5,那么a2+a11的值为( )
【单选题】在等差数列{a n }中,如果前5项的和为S 5 =20,那么a 3 等于( )
【单选题】He said. “Since that is the case, let us invite Wealth. Let him come in and (fill our home with wealth)!”
【简答题】在等差数列{a n }中,已知a 1 +a 2 +a 3 +a 4 +a 5 =20,那么a 3 =( ) A.4 B.5 C.6 D.7