GRE数学几何题例题分析
<p> 新<span word="GRE">GRE</span>数学考试几何题经典讲解如下：</p><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> 3.三角形三边为8,5,6,问5,6 夹角于90谁大?</p><p> <span word="mykey">mykey</span>:前者大.</p><p> 4.圆里头最长的线段是哪条?</p><p> 就是直径</p><p> 5.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> 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> 解:两点式:列出两点,<span word="k">k</span>=/=-<span word="b">b</span>/<span word="a">a</span></p><p> 6.图中一三角形,<span word="X">X</span>,,<span word="Z">Z</span>分别为两个角的外角,<span word="Y">Y</span>为第三个内角,问<span word="X">X</span>+<span word="Z">Z</span>与180+<span word="Y">Y</span>的大小?</p><p> 解: <span word="Y">Y</span>++=180</p><p> 可退出<span word="Y">Y</span>+180= <span word="X">X</span>+<span word="Z">Z</span> 所以相等</p><p> 7.钝角三角形，两短边为6，8，问其面积与24的大小。</p><p> 解:</p><p> 8.三角形三条边6，8，10.5，问6和8所对的两个角相加与90度比</p><p> 解:小于。</p>
页:
[1]