费费数学宝典(连载七)
<p> 以下为大家连载<span word="GMAT">GMAT</span>数学考试备考宝书，费费数学宝典，希望大家备考顺利，成绩高高，都能申请到理想的美国大学!</p><p> 6、1+<span word="X">X</span>+<span word="X">X</span>^2+<span word="X">X</span>^3+<span word="X">X</span>^4+<span word="X">X</span>^51/?</p><p> (1)<span word="X">X</span>0</p><p> (2)<span word="X">X</span>1</p><p> 【答案】<span word="C">C</span></p><p> 【思路】</p><p> (1)不可。因<span word="x">x</span>=1搞定。</p><p> (2)不可。</p><p> (1)(2)合起来，1-<span word="x">x</span>^20，可以。</p><p> + <span word="x">x</span>^2+<span word="X">X</span>^41/</p><p> +<span word="x">x</span>^2+<span word="x">x</span>^41</p><p> 1</p><p> + <span word="x">x</span>^41</p><p> 1-<span word="x">x</span>^4+<span word="x">x</span>^4-<span word="x">x</span>^61</p><p> 1-<span word="x">x</span>^61</p><p> 7、<span word="N">N</span>为1-99之间的整数，问满足<span word="N">N</span>被3整除的<span word="N">N</span>的概率。</p><p> 【答案】2/3</p><p> 【思路】</p><p> 1、2、3中，2、3两个数符合条件<span word="n">n</span>能被3整除的条件，由于3个数一循环，所以比例为2/3。</p><p> </p>
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