[求助]两道数学题

ceciliading

1.For any positive integer x, the
    "2-height" of x

is defined to be the greatest nonnegative

integer n such that 2^n is a factor of x.if k

and m are positive integers,,what is the 2-height

of k greater than the 2-height of m ?

(1) k>m

(2) k/m is an even integer

选B,不知道怎么求解出来的

是XDF书上的一道,FEIFEI中也有一道类似的,但是是PS,(如下),我似乎有点搞起来了,愣是没看懂,请好心人指教~万分感谢!

2.For all x, x is positive integer,  "2-height" is defined

    to be the greatest nonnegative n of x, what is the

    greatest number of 2-height when 2" is the factor of x?

A. 2

B. 12

C. 40

D. 76

E. 90

选C?!

[此贴子已经被作者于2008-1-21 0:12:38编辑过]

ceciliading

哪位朋友知道呀,帮忙解答下,非常感谢呢!

mmscute

题目细节都对吗

suwendao

i just try

it means to find the greatest n, for first question 2^n+1>2^n since k/m is even number, so 2-height of k surely larger than 2-height of m; but if k/m>1, that's not true. For eg, 12/4, 2 height same for them.

2nd qn, easy to find that 40 has 8=2^3, 3 is the greastest n among those 5 numbers.

ceciliading

谢谢LS的~~~