新版gre数学复习重要考点：Sum of Arithmetic Progression
<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> 所以，从今天起，针对新版<span word="gre">gre</span>数学复习，小编每天给考生整理一个重要考点，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="Sum">Sum</span> <span word="of">of</span> <span word="Arithmetic">Arithmetic</span> <span word="Progression">Progression</span></p><p> <span word="The">The</span> <span word="sum">sum</span> <span word="of">of</span> <span word="n">n</span>-<span word="numbers">numbers</span> <span word="of">of</span> <span word="an">an</span> <span word="arithmetic">arithmetic</span> <span word="progression">progression</span> <span word="is">is</span> <span word="given">given</span> <span word="by">by</span></p><p> <span word="S">S</span>=<span word="nxdn">nxdn</span>/2</p><p> <span word="where">where</span> <span word="x">x</span> <span word="is">is</span> <span word="the">the</span> <span word="first">first</span> <span word="number">number</span> <span word="and">and</span> <span word="d">d</span> <span word="is">is</span> <span word="the">the</span> <span word="constant">constant</span> <span word="increment">increment</span>.</p><p> <span word="example">example</span>:</p><p> <span word="sum">sum</span> <span word="of">of</span> <span word="first">first</span> 10 <span word="positive">positive</span> <span word="odd">odd</span> <span word="numbers">numbers</span>:101+2109/2=10+90=100</p><p> <span word="sum">sum</span> <span word="of">of</span> <span word="first">first</span> 10 <span word="multiples">multiples</span> <span word="of">of</span> 7 <span word="starting">starting</span> <span word="at">at</span> 7: 107+7109/2=70+315=385</p><p> <span word="remember">remember</span>:</p><p> <span word="For">For</span> <span word="a">a</span> <span word="descending">descending</span> <span word="AP">AP</span> <span word="the">the</span> <span word="constant">constant</span> <span word="difference">difference</span> <span word="is">is</span> <span word="negative">negative</span>.</p><p> </p>
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