{}是首项为1，公比为sinα()的等比数列，又

已知数列是首项的等比数列，且，是首项为1的等差数列，又                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    

（1）求数列的通项公式；（2）求数列的前项和.

设等比数列{an}的首项为a1，公比为q，则“a1＜0，且0＜q＜1”是“对于任意n∈N*都有an+1＞an”的（    ）            （    ）

A．充分不必要条件       B．必要不充分条件

C．充分比要条件     D．既不充分又不必要条件