5.如果(a-1)x>1-a的解是x<-1,那么a必须满足( )
| A. | a<0 | B. | a<-1 | C. | a>-1 | D. | a<1 |
2.
如图,CB、CD分别是钝角三角形AEC和锐角三角形ABC的中线,且∠ACB=∠ABC,AB=AC,给出下列结论:①AE=2AC;②CE=2CD;③∠ACD=∠BCE;④CB是∠DCE的平分线.正确的结论序号是( )
| A. | ①②③ | B. | ①②④ | C. | ①②③④ | D. | ②③④ |
1.
如图,点P是圆锥的顶点,AB是圆锥的底面直径,且PA=$\frac{3}{2}$AB,点C、D是底面圆周上的两点,满足AC=CD=DB.则在该圆锥的侧面展开图上,∠CPD的度数为( )
0 286829 286837 286843 286847 286853 286855 286859 286865 286867 286873 286879 286883 286885 286889 286895 286897 286903 286907 286909 286913 286915 286919 286921 286923 286924 286925 286927 286928 286929 286931 286933 286937 286939 286943 286945 286949 286955 286957 286963 286967 286969 286973 286979 286985 286987 286993 286997 286999 287005 287009 287015 287023 366461
| A. | 15° | B. | 20° | C. | 30° | D. | 60° |