95. xy<1 (1) x+y<1 (2) x^2+y^2=1 Ans: B |x|<1,|y|<1,又x,y不能同时为-1或者1 227. DS题:n是一个两位数,包括1和n在内有8个factor,the value of n? (1) n is mutiple of 18
(2) 50<=n<=60 我选的是E 54和56都满足 Ans: A (1) n= 18 (6 factor), 36 (9 factor), 54 (8 factor), 72 (12 factor), 90 (12 factor) (2) n= 50 (6 factor), 51 (4 factor), 52 (6 factor), 53 (4 factor), 54 (8 factor), 55 (4 factor), 56 (8 factor), 57 (4 factor), 58 (4 factor), 59 (2 factor), 60 (12 factor)
这两题究竟哪个是正确答案,明天就考了,着急啊!!! |