(本小题满分12分) 等差数列中,首项,公差,前n项和为,已知数列成等比数列,其中,,. (Ⅰ)求数列,的通项公式; (Ⅱ)令,数列的前n项
关于今年我国台风偏多的原因叙述中,正确的是 ( ) A.赤道辐合带异常活跃
Few men________ shopping with their wives ________ at home to watch TV. A.prefer going,to staying B.prefer to go,to shopping C.would rather to go
Go for it while you are young. You can’t avoid _________ your job tomorrow unless you work hard today. A. losing B. to lose
一个在空中飞行的手雷,以水平速度v飞经离地面高为h的轨道最高点时,炸裂成A、B两块,A、B质量之比为n(少量炸药质量不计).之后,B正好自由下落
下图中服装的款式最早出现于: ( )A.鸦片战争期间 B.洋务运动期间 C.戊戌变法期间 D.辛亥革命后
下列关系式中正确的是( ) A.sin 11°<cos 10°<sin 168° B.sin 168°<sin 11°<cos 10° C.sin 11°<sin 168°<cos 10° D.sin 168°<cos 10°<si