A:1.0 m/
B:10 m/
C:2.0 m/
D:20 m/
小勇在江边拾到一块鹅卵石,他想知道这块鹅卵石的密度.
— It's not officially confirmed yet. The committee are _________ it over.
已知一次函数fx=kx+b的图像经过点P1,2和Q-2,-4,令an=fnfn+1,n∈N*,记数列1an的前项和为Sn,当Sn=625时,n的值等于( )