GRE数学难点解析
<p> 1、两条直线比斜率：</p><p> 一条<span word="x">x</span>轴<span word="intercede">intercede</span> 3，<span word="y">y</span>轴<span word="intercede">intercede</span> 4， 和一条<span word="x">x</span>轴<span word="intercede">intercede</span> 4，一个<span word="y">y</span>轴<span word="intercede">intercede</span> 3。</p><p> 解：<span word="slope">slope</span>1=/=-4/3 <span word="slop">slop</span>2=/=-3/4</p><p> 注意由于两条直线的斜率是负数， 后者斜率大一些。</p><p> 2、直线<span word="y">y</span>+<span word="x">x</span>=4， 与<span word="x">x</span>^2+<span word="y">y</span>=4交点的距离?</p><p> 解：<span word="meykey">meykey</span>：根号2。 4-<span word="x">x</span>=4-<span word="x">x</span>2</p><p> 3、有一个题目觉得很有意思，就是问<span word="y">y</span>=<span word="xx">xx</span>+1和<span word="y">y</span>=<span word="x">x</span>-1的图是下列哪一个?</p><p> 比较简单。选的是<span word="D">D</span>。</p><p> 4、一直线在<span word="X">X</span>轴截距为<span word="a">a</span>，<span word="Y">Y</span>轴上截距为<span word="b">b</span>，问斜率是多少。</p><p> 现在已经是新<span word="GRE">GRE</span>时代了，新<span word="GRE">GRE</span>数学难度会随第一个<span word="section">section</span>的准确率而相应的提高难度，这是众所周知的事情了。那么新<span word="GRE">GRE</span>数学疑难问题解答思路有哪些?怎样解答新<span word="GRE">GRE</span>数学中的疑难问题呢?请看下文的解析。</p><p> 1.从2 3 4 5 6 7 8 9中取数字组成三位数号码，<span word="assign">assign</span> <span word="to">to</span> 330 <span word="employee">employee</span>, 数字不重复， 问多少号码<span word="unassigned">unassigned</span>?</p><p> 解：<span word="P">P</span>==336</p><p> 336-330=6</p><p> 2.一个工作<span word="W">W</span>，<span word="X">X</span>做要比<span word="Y">Y</span>做少两天，<span word="X">X</span>，<span word="Y">Y</span>一起做4/3<span word="W">W</span>要3天，求<span word="X">X</span>单独做2<span word="W">W</span>要几天?</p><p> 解：令<span word="W">W</span>/<span word="X">X</span>=<span word="x">x</span>，<span word="W">W</span>/<span word="Y">Y</span>=<span word="y">y</span>，则<span word="x">x</span>+2=<span word="y">y</span></p><p> /=3</p><p> 两式连立化去<span word="y">y</span>，即可解得<span word="x">x</span></p>
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