Bài 2. Phép tịnh tiến
Hướng dẫn giải Hoạt động 3 (Trang 7 SGK Toán Hình học 11)
<p><strong class="content_question">Đề b&agrave;i</strong></p> <p>Trong mặt phẳng tọa độ <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>O</mi><mi>x</mi><mi>y</mi></math>&nbsp;cho vecto <math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mi>v</mi><mo>&rarr;</mo></mover><mo>=</mo><mfenced><mrow><mn>1</mn><mo>;</mo><mn>2</mn></mrow></mfenced></math>. T&igrave;m tọa độ của điểm<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>M</mi><mo>'</mo></math> l&agrave; ảnh của điểm <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>M</mi><mfenced><mrow><mn>3</mn><mo>;</mo></mrow></mfenced></math></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mfenced><mrow><mo>-</mo><mn>1</mn></mrow></mfenced></math>&nbsp;qua ph&eacute;p tịnh tiến&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>T</mi><mover><mi>v</mi><mo>&rarr;</mo></mover></math></p> <p><strong class="content_detail">Lời giải chi tiết</strong></p> <p>Gọi <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>M</mi><mfenced><mrow><mi>x</mi><mo>'</mo><mo>;</mo><mi>y</mi><mo>'</mo></mrow></mfenced></math>&nbsp;l&agrave; ảnh của <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>M</mi></math>&nbsp;qua ph&eacute;p tịnh tiến theo vecto&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mi>v</mi><mo>&rarr;</mo></mover></math></p> <p>Ta c&oacute;: &nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>M</mi><mfenced><mrow><mn>3</mn><mo>;</mo><mo>-</mo><mn>1</mn></mrow></mfenced></math> v&agrave;&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mi>v</mi><mo>&rarr;</mo></mover><mo>=</mo><mfenced><mrow><mn>1</mn><mo>;</mo><mn>2</mn></mrow></mfenced></math></p> <p><span id="MathJax-Element-11-Frame" class="mjx-chtml MathJax_CHTML" style="margin: 0px; padding: 1px 0px; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 21.78px; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;" tabindex="0" role="presentation" data-mathml="&lt;math xmlns=&quot;http://www.w3.org/1998/Math/MathML&quot;&gt;&lt;mtable columnalign=&quot;right left&quot; rowspacing=&quot;.5em&quot; columnspacing=&quot;thickmathspace&quot; displaystyle=&quot;true&quot;&gt;&lt;mtr&gt;&lt;mtd /&gt;&lt;mtd&gt;&lt;mo stretchy=&quot;false&quot;&gt;&amp;#x21D2;&lt;/mo&gt;&lt;mrow&gt;&lt;mo&gt;{&lt;/mo&gt;&lt;mtable rowspacing=&quot;4pt&quot; columnspacing=&quot;1em&quot;&gt;&lt;mtr&gt;&lt;mtd columnalign=&quot;left&quot;&gt;&lt;msup&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;mo&gt;&amp;#x2032;&lt;/mo&gt;&lt;/msup&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mtd&gt;&lt;/mtr&gt;&lt;mtr&gt;&lt;mtd columnalign=&quot;left&quot;&gt;&lt;msup&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;mo&gt;&amp;#x2032;&lt;/mo&gt;&lt;/msup&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mo&gt;&amp;#x2212;&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mtd&gt;&lt;/mtr&gt;&lt;/mtable&gt;&lt;mo fence=&quot;true&quot; stretchy=&quot;true&quot; symmetric=&quot;true&quot;&gt;&lt;/mo&gt;&lt;/mrow&gt;&lt;/mtd&gt;&lt;/mtr&gt;&lt;/mtable&gt;&lt;/math&gt;"><span id="MJXc-Node-79" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-80" class="mjx-mrow"><span id="MJXc-Node-81" class="mjx-mtable"><span class="mjx-table"><span id="MJXc-Node-82" class="mjx-mtr"><span id="MJXc-Node-83" class="mjx-mtd"><span id="MJXc-Node-84" class="mjx-mrow"></span></span><span id="MJXc-Node-85" class="mjx-mtd"><span id="MJXc-Node-86" class="mjx-mrow"><span id="MJXc-Node-87" class="mjx-mo"><span class="mjx-char MJXc-TeX-main-R">&rArr;<math xmlns="http://www.w3.org/1998/Math/MathML"><mfenced open="{" close=""><mtable columnalign="left"><mtr><mtd><mi>x</mi><mo>'</mo><mo>=</mo><mn>3</mn><mo>+</mo><mn>1</mn></mtd></mtr><mtr><mtd><mi>y</mi><mo>'</mo><mo>=</mo><mo>-</mo><mn>1</mn><mo>+</mo><mn>2</mn></mtd></mtr></mtable></mfenced></math><math xmlns="http://www.w3.org/1998/Math/MathML"><mo>&rArr;</mo><mfenced open="{" close=""><mtable columnalign="left"><mtr><mtd><mi>x</mi><mo>'</mo><mo>=</mo><mn>4</mn></mtd></mtr><mtr><mtd><mi>y</mi><mo>'</mo><mo>=</mo><mn>1</mn></mtd></mtr></mtable></mfenced></math></span></span><span id="MJXc-Node-88" class="mjx-mrow MJXc-space3"><span id="MJXc-Node-89" class="mjx-mo"></span></span></span></span></span></span></span></span></span></span><math xmlns="http://www.w3.org/1998/Math/MathML"><mtable columnalign="right left" rowspacing=".5em" columnspacing="thickmathspace" displaystyle="true"><mtr><mtd><mrow><mtable rowspacing="4pt" columnspacing="1em"><mtr><mtd columnalign="left"><mn></mn></mtd></mtr></mtable><mo fence="true" stretchy="true" symmetric="true"></mo></mrow></mtd></mtr></mtable></math></p> <p>Vậy <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>M</mi><mo>'</mo><mfenced><mrow><mn>4</mn><mo>;</mo><mn>1</mn></mrow></mfenced></math>&nbsp;l&agrave; ảnh của <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>M</mi></math>&nbsp;qua ph&eacute;p tịnh tiến theo&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mi>v</mi><mo>&rarr;</mo></mover></math></p> <p>&nbsp;</p>
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