四大SAT数学解题方法全面解析
<p> 在这里想和大家一起探讨一下<span word="SAT">SAT</span>数学解题方法，<span word="SAT">SAT</span>数学是中国学生的强项，我们在运用<span word="SAT">SAT</span>数学解题方法时也会觉得得心应手。因为<span word="NEW">NEW</span> <span word="SAT">SAT</span>数学考察范围包括算术及应用题、代数及函数、几何及度量衡、数据分析、统计学及基础概率论。当然这些内容中的绝大部分在中国大陆的数学教学中高二之前就已经全部学习完毕了。</p><p> 在一次完整的<span word="New">New</span> <span word="SAT">SAT</span>考试里，数学部分一共包括3个<span word="Section">Section</span> ，其中2个<span word="Section">Section</span>各需在25分钟内完成，1个<span word="Section">Section</span>需要在20分钟内完成。题型则分为两种：选择题和填写空格题。</p><p> 给大家介绍几种常见的数学解题方法：</p><p> 1. 代入法</p><p> 例题：<span word="If">If</span> <span word="x">x</span> <span word="and">and</span> <span word="y">y</span> <span word="are">are</span> <span word="two">two</span> <span word="different">different</span> <span word="integers">integers</span> <span word="and">and</span> <span word="the">the</span> <span word="product">product</span> 35<span word="xy">xy</span> <span word="is">is</span> <span word="the">the</span> <span word="square">square</span> <span word="of">of</span> <span word="an">an</span> <span word="integer">integer</span>, <span word="which">which</span> <span word="of">of</span> <span word="the">the</span> <span word="following">following</span> <span word="could">could</span> <span word="be">be</span> <span word="equal">equal</span> <span word="to">to</span> <span word="xy">xy</span>?</p><p> <span word="A">A</span>. 5 <span word="B">B</span>.70 <span word="C">C</span>. 105 <span word="D">D</span>. 140 <span word="E">E</span>. 350解答：将答案依次带入，发现只有<span word="D">D</span>选项35<span word="xy">xy</span>=35140=35354=2。</p><p> 2. 特殊值法</p><p> 例题：<span word="xy">xy</span>=<span word="x">x</span>+<span word="y">y</span>. <span word="If">If</span> <span word="y">y</span>2, <span word="what">what</span> <span word="are">are</span> <span word="all">all</span> <span word="possible">possible</span> <span word="values">values</span> <span word="of">of</span> <span word="x">x</span> <span word="that">that</span> <span word="satisfy">satisfy</span> <span word="the">the</span> <span word="equation">equation</span> <span word="above">above</span>?</p><p> <span word="A">A</span>. <span word="x">x</span>0, <span word="B">B</span>. 0</p><p> 解答：<span word="y">y</span>2,不妨假设它为3，3<span word="x">x</span>=<span word="x">x</span>+3,<span word="x">x</span>=3/2,一目了然<span word="D">D</span>即为正确选项。</p><p> 3. 巧解法</p><p> 例题：<span word="At">At</span> <span word="a">a</span> <span word="certain">certain</span> <span word="diner">diner</span>, <span word="Joe">Joe</span> <span word="orders">orders</span> 3 <span word="doughnuts">doughnuts</span> <span word="and">and</span> <span word="a">a</span> <span word="cup">cup</span> <span word="of">of</span> <span word="coffee">coffee</span> <span word="and">and</span> <span word="is">is</span> <span word="charged">charged</span> $2.25. <span word="Stella">Stella</span> <span word="orders">orders</span> 2 <span word="doughnuts">doughnuts</span> <span word="and">and</span> <span word="a">a</span> <span word="cup">cup</span> <span word="of">of</span> <span word="coffee">coffee</span> <span word="and">and</span> <span word="is">is</span> <span word="charged">charged</span> $1.70. <span word="What">What</span> <span word="is">is</span> <span word="the">the</span> <span word="price">price</span> <span word="of">of</span> 2 <span word="doughnuts">doughnuts</span>?</p>
页:
[1]