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{}是首項為1，公比為sinα()的等比數(shù)列，又

已知數(shù)列是首項的等比數(shù)列，且，是首項為1的等差數(shù)列，又                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    

（1）求數(shù)列的通項公式；（2）求數(shù)列的前項和.

設等比數(shù)列{an}的首項為a1，公比為q，則“a1＜0，且0＜q＜1”是“對于任意n∈N*都有an+1＞an”的（    ）            （    ）

A．充分不必要條件       B．必要不充分條件

C．充分比要條件     D．既不充分又不必要條件