A.![]() | B.![]() | C.[-2,3] | D.[1,6] |
A.![]() | B.![]() | C.1 | D.2 |
A.2 | B.2![]() | C.4 | D.2![]() |
A.![]() | B.![]() |
C.(3,+∞) | D.(4,+∞) |
A.(4,+∞) | B.[-4,+∞) |
C.(-∞,-4] | D.(-∞,-4) |
A.2 | B.1 | C.-2 | D.-3 |
A.|b-a+![]() | B.a3b+b3c+c3a≥a4+b4+c4 |
C.b2>ac | D.|b|-|a|≤|c|-|b| |
A.![]() | B.1 | C.2 | D.4 |
A.A,B为定点,动点P满足|PA|+|PB|=2a>|AB|,则P点的轨迹为椭圆 |
B.由a1=1,an=3n-1,求出S1,S2,S3,猜想出数列的前n项和Sn的表达式 |
C.由圆x2+y2=r2的面积πr2,猜想出椭圆![]() ![]() |
D.以上均不正确 |
A.[-1,4] |
B.(-∞,-1]∪[4,+∞) |
C.(-3,5) |
D.(-∞,-3)∪[-1,4]∪(5,+∞) |
时间(将第x天记为x)x | 1 | 10 | 11 | 18 |
单价(元/件)P | 9 | 0 | 1 | 8 |