Bài 6: Sô vô tỉ. Căn bậc hai số học
Luyện tập 2 (Trang 31 SGK Toán 7, Bộ Kết nối tri thức với cuộc sống, Tập 1)
<p><strong>Luyện tập 2 (Trang 31 SGK To&aacute;n 7, Bộ Kết nối tri thức với cuộc sống, Tập 1)</strong></p> <p>Sử dụng m&aacute;y t&iacute;nh cầm tay t&iacute;nh c&aacute;c căn bậc hai số học sau (l&agrave;m tr&ograve;n kết quả với độ ch&iacute;nh x&aacute;c 0,005, nếu cần).</p> <p>a)&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mn>15</mn></msqrt><mo>;</mo></math></p> <p>b)&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mn>2</mn><mo>,</mo><mn>56</mn></msqrt><mo>;</mo></math></p> <p>c)&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mn>17</mn><mo>&nbsp;</mo><mn>256</mn></msqrt><mo>;</mo></math></p> <p>d)&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mn>793</mn><mo>&nbsp;</mo><mn>881</mn></msqrt><mo>.</mo></math></p> <p><em><strong>Hướng dẫn giải</strong></em></p> <p align="left">Độ ch&iacute;nh x&aacute;c 0,005 tức l&agrave; ta cần l&agrave;m tr&ograve;n đến h&agrave;ng phần trăm</p> <p align="left">a)&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mn>15</mn></msqrt><mo>&nbsp;</mo><mo>&asymp;</mo><mo>&nbsp;</mo><mn>3</mn><mo>,</mo><mn>87</mn><mo>;</mo></math></p> <p align="left">b)&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mn>2</mn><mo>,</mo><mn>56</mn></msqrt><mo>&nbsp;</mo><mo>&asymp;</mo><mn>1</mn><mo>,</mo><mn>6</mn><mo>;</mo></math></p> <p align="left">c)&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mn>17</mn><mo>&nbsp;</mo><mn>256</mn></msqrt><mo>&nbsp;</mo><mo>&asymp;</mo><mo>&nbsp;</mo><mn>131</mn><mo>,</mo><mn>36</mn><mo>;</mo></math></p> <p align="left">d)&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mn>793</mn><mo>&nbsp;</mo><mn>881</mn></msqrt><mo>&nbsp;</mo><mo>=</mo><mo>&nbsp;</mo><mn>891</mn><mo>.</mo></math></p> <p align="left"><span id="MathJax-Element-2-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: 16.94px; 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;left&quot; rowspacing=&quot;4pt&quot; columnspacing=&quot;1em&quot;&gt;&lt;mtr&gt;&lt;mtd&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mo stretchy=&quot;false&quot;&gt;)&lt;/mo&gt;&lt;msqrt&gt;&lt;mn&gt;15&lt;/mn&gt;&lt;/msqrt&gt;&lt;mo&gt;&amp;#x2248;&lt;/mo&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;87&lt;/mn&gt;&lt;/mtd&gt;&lt;/mtr&gt;&lt;mtr&gt;&lt;mtd&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;mo stretchy=&quot;false&quot;&gt;)&lt;/mo&gt;&lt;msqrt&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;56&lt;/mn&gt;&lt;/msqrt&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;6&lt;/mn&gt;&lt;/mtd&gt;&lt;/mtr&gt;&lt;mtr&gt;&lt;mtd&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;mo stretchy=&quot;false&quot;&gt;)&lt;/mo&gt;&lt;msqrt&gt;&lt;mn&gt;17256&lt;/mn&gt;&lt;/msqrt&gt;&lt;mo&gt;&amp;#x2248;&lt;/mo&gt;&lt;mn&gt;131&lt;/mn&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mn&gt;36&lt;/mn&gt;&lt;/mtd&gt;&lt;/mtr&gt;&lt;mtr&gt;&lt;mtd&gt;&lt;mi&gt;d&lt;/mi&gt;&lt;mo stretchy=&quot;false&quot;&gt;)&lt;/mo&gt;&lt;msqrt&gt;&lt;mn&gt;793881&lt;/mn&gt;&lt;/msqrt&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;891&lt;/mn&gt;&lt;/mtd&gt;&lt;/mtr&gt;&lt;/mtable&gt;&lt;/math&gt;"><span id="MJXc-Node-28" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-29" class="mjx-mrow"><span id="MJXc-Node-30" class="mjx-mtable"><span class="mjx-table"><span id="MJXc-Node-31" class="mjx-mtr"><span id="MJXc-Node-32" class="mjx-mtd"><span id="MJXc-Node-33" class="mjx-mrow"><span id="MJXc-Node-34" class="mjx-mi"></span></span></span></span></span></span></span></span></span></p> <p>&nbsp;</p>
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