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Q29: For which real numbers x is the expression 1/(x+1)(x-2) not defined? A. x = 0 only
B. x = 2 only C. x = –1 only D. x = –1 or 2 E. x = –1, 0 or 2 答案是(D) 这题的思路我不太懂，分母不得为0的话，X不等于–1 or 2 可是B, C, E也是有这二个数字啊，如果X=–1 or 2的话不就无意义了吗?? 请高手指点....谢谢 Q31: Phobus, one of the satellites of Mars, revolves about Mars at a distance of approximately 5,800 miles from the center of Mars and approximately 3,700 miles from the surface of Mars. If it is assumed that Mars is spherical and the orbit of Phobus is circular, what is the approximate circumference, in miles, of Mars at its equator?
A. 2,100π B. 4,200π C. 7,400π D. 9,500π E. 190,000π 答案是(B), 说实在的，看不懂题目是什么意思...请高手帮忙! 谢谢  | 
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发表于 2008-8-12 22:22:00
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