新版gre数学复习重要考点：Substitution
<p> 俗话说：工欲善其事必先利其器。很多参加了新版<span word="gre">gre</span>考试的同学都觉得数学有点难度，相信这其中的原因还是由于考生在新版<span word="gre">gre</span>数学复习时没有把基础打牢。如果新版<span word="gre">gre</span>数学基本考点都没有复习到，如何能拿到分数呢?所以说，想要新版<span word="gre">gre</span>数学考好，复习的时候一定要把基本概念和重要考点都弄扎实。</p><p> 今天针对新版<span word="gre">gre</span>数学复习，小编给大家整理的是关于<span word="Substitution">Substitution</span>的相关内容，这些概念在考试中一定会考到的。希望考生能再接再厉，取得一个好成绩，突破新版<span word="gre">gre</span>数学难的困境。</p><p> 新版<span word="gre">gre</span>数学复习重要考点：<span word="Substitution">Substitution</span></p><p> <span word="Substitution">Substitution</span> <span word="is">is</span> <span word="a">a</span> <span word="method">method</span> <span word="where">where</span> <span word="one">one</span> <span word="or">or</span> <span word="more">more</span> <span word="variables">variables</span> <span word="in">in</span> <span word="an">an</span> <span word="expression">expression</span> <span word="is">is</span> <span word="replaced">replaced</span> <span word="by">by</span> <span word="numbers">numbers</span> <span word="or">or</span> <span word="another">another</span> <span word="set">set</span> <span word="of">of</span> <span word="variables">variables</span>.<span word="To">To</span> <span word="evaluate">evaluate</span> <span word="an">an</span> <span word="expression">expression</span> <span word="specific">specific</span> <span word="numbers">numbers</span> <span word="are">are</span> <span word="used">used</span> <span word="as">as</span> <span word="substitute">substitute</span>. <span word="To">To</span> <span word="express">express</span> <span word="in">in</span> <span word="terms">terms</span> <span word="of">of</span> <span word="another">another</span> <span word="set">set</span> <span word="of">of</span> <span word="variables">variables</span>, <span word="variables">variables</span> <span word="are">are</span> <span word="replaced">replaced</span> <span word="by">by</span> <span word="the">the</span> <span word="new">new</span> <span word="set">set</span> <span word="of">of</span> <span word="variables">variables</span>.</p><p> <span word="Example">Example</span>:</p><p> <span word="If">If</span> <span word="x">x</span>=3, <span word="then">then</span> 2<span word="x">x</span>2+4<span word="x">x</span>+1 <span word="can">can</span> <span word="be">be</span> <span word="evaluated">evaluated</span> <span word="by">by</span> <span word="substituting">substituting</span> 3 <span word="for">for</span> <span word="x">x</span>.</p><p> <span word="Replacing">Replacing</span> <span word="all">all</span> <span word="x">x</span> <span word="by">by</span> 3, <span word="we">we</span> <span word="get">get</span> 232+43+1=31.</p><p> <span word="If">If</span> <span word="x">x</span>=2+<span word="y">y</span>, <span word="then">then</span> <span word="x">x</span>2-3 <span word="can">can</span> <span word="be">be</span> <span word="expressed">expressed</span> <span word="in">in</span> <span word="terms">terms</span> <span word="of">of</span> <span word="y">y</span> <span word="by">by</span> <span word="replacing">replacing</span> <span word="all">all</span> <span word="x">x</span> <span word="by">by</span> :2-3=<span word="y">y</span>2+4<span word="y">y</span>+1.</p><p> <span word="Remember">Remember</span>:</p><p> <span word="Do">Do</span> <span word="not">not</span> <span word="forget">forget</span> <span word="to">to</span> <span word="replace">replace</span> <span word="all">all</span> <span word="occurrences">occurrences</span> <span word="of">of</span> <span word="the">the</span> <span word="variable">variable</span>.</p><p> <span word="After">After</span> <span word="substitution">substitution</span> <span word="the">the</span> <span word="variable">variable</span> <span word="does">does</span> <span word="not">not</span> <span word="appear">appear</span> <span word="anywhere">anywhere</span> <span word="in">in</span> <span word="the">the</span> <span word="expression">expression</span>.</p>
页:
[1]