Bài tập cuối chương 1
Hướng dẫn giải Bài 5 (Trang 19, SGK Toán, Bộ Cánh Diều mới nhất, Tập 1)
<p><strong>B&agrave;i 5 (Trang 19, SGK To&aacute;n, Bộ C&aacute;nh diều, Tập 1)</strong></p> <p>D&ugrave;ng k&iacute; hiệu để viết mỗi tập hợp sau v&agrave; biểu diễn mỗi tập hợp đ&oacute; tr&ecirc;n trục số.</p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>a</mi><mo>)</mo><mo>&#160;</mo><mi>A</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfenced open="{" close="}"><mrow><mi>x</mi><mo>&#160;</mo><mo>&#8712;</mo><mo>&#160;</mo><mi mathvariant="normal">&#8477;</mi><mo>|</mo><mo>&#160;</mo><mo>-</mo><mn>2</mn><mo>&#160;</mo><mo>&#60;</mo><mo>&#160;</mo><mi>x</mi><mo>&#160;</mo><mo>&#60;</mo><mo>&#160;</mo><mo>-</mo><mn>1</mn></mrow></mfenced><mo>;</mo><mspace linebreak="newline"/><mi>b</mi><mo>)</mo><mo>&#160;</mo><mi>B</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfenced open="{" close="}"><mrow><mi>x</mi><mo>&#160;</mo><mo>&#8712;</mo><mo>&#160;</mo><mi mathvariant="normal">&#8477;</mi><mo>|</mo><mo>&#160;</mo><mo>-</mo><mn>3</mn><mo>&#160;</mo><mo>&#8804;</mo><mo>&#160;</mo><mi>x</mi><mo>&#160;</mo><mo>&#8804;</mo><mo>&#160;</mo><mn>0</mn></mrow></mfenced><mo>;</mo><mspace linebreak="newline"/><mi>c</mi><mo>)</mo><mo>&#160;</mo><mi>C</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfenced open="{" close="}"><mrow><mi>x</mi><mo>&#160;</mo><mo>&#8712;</mo><mo>&#160;</mo><mi mathvariant="normal">&#8477;</mi><mo>|</mo><mo>&#160;</mo><mi>x</mi><mo>&#160;</mo><mo>&#8804;</mo><mo>&#160;</mo><mn>1</mn></mrow></mfenced><mo>;</mo><mspace linebreak="newline"/><mi>d</mi><mo>)</mo><mo>&#160;</mo><mi>D</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfenced open="{" close="}"><mrow><mi>x</mi><mo>&#160;</mo><mo>&#8712;</mo><mo>&#160;</mo><mi mathvariant="normal">&#8477;</mi><mo>|</mo><mo>&#160;</mo><mi>x</mi><mo>&#160;</mo><mo>&#62;</mo><mo>-</mo><mn>2</mn></mrow></mfenced><mo>.</mo></math></p> <p><strong><span style="text-decoration: underline;"><em>Hướng dẫn giải:</em></span></strong></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>a</mi><mo>)</mo><mo>&#160;</mo><mi>A</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfenced open="{" close="}"><mrow><mi>x</mi><mo>&#160;</mo><mo>&#8712;</mo><mo>&#160;</mo><mi mathvariant="normal">&#8477;</mi><mo>|</mo><mo>&#160;</mo><mo>-</mo><mn>2</mn><mo>&#160;</mo><mo>&#60;</mo><mo>&#160;</mo><mi>x</mi><mo>&#160;</mo><mo>&#60;</mo><mo>&#160;</mo><mo>-</mo><mn>1</mn></mrow></mfenced><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>(</mo><mo>-</mo><mn>2</mn><mo>;</mo><mo>-</mo><mn>1</mn><mo>)</mo></math></p> <p>Ta biểu diễn tập hợp A (phần m&agrave;u đỏ) như sau:</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/17062022/z3499415600353_08515b1b6a3fc7411f4bc8254249e5d9-98r7Ah.jpg" /></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>b</mi><mo>)</mo><mo>&#160;</mo><mi>B</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfenced open="{" close="}"><mrow><mi>x</mi><mo>&#160;</mo><mo>&#8712;</mo><mo>&#160;</mo><mi mathvariant="normal">&#8477;</mi><mo>|</mo><mo>&#160;</mo><mo>-</mo><mn>3</mn><mo>&#160;</mo><mo>&#8804;</mo><mo>&#160;</mo><mi>x</mi><mo>&#160;</mo><mo>&#8804;</mo><mo>&#160;</mo><mn>0</mn></mrow></mfenced><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>[</mo><mo>-</mo><mn>3</mn><mo>;</mo><mn>0</mn><mo>]</mo></math></p> <p>Ta biểu diễn tập hợp B (phần m&agrave;u đỏ) như sau:</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/17062022/z3499416088655_2468040c5c9562e6cee8d072ee42d6e2-7gFuYJ.jpg" /></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>c</mi><mo>)</mo><mo>&#160;</mo><mi>C</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfenced open="{" close="}"><mrow><mi>x</mi><mo>&#160;</mo><mo>&#8712;</mo><mo>&#160;</mo><mi mathvariant="normal">&#8477;</mi><mo>|</mo><mo>&#160;</mo><mi>x</mi><mo>&#160;</mo><mo>&#8804;</mo><mo>&#160;</mo><mn>1</mn></mrow></mfenced><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>(</mo><mo>-</mo><mo>&#8734;</mo><mo>;</mo><mn>1</mn><mo>]</mo></math></p> <p>Ta biểu diễn tập hợp C (phần m&agrave;u đỏ) như sau:</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/17062022/z3499416602895_90582f5da4a1f09ed325aa435d4fb5d7-X0u495.jpg" /></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>d</mi><mo>)</mo><mo>&#160;</mo><mi>D</mi><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mfenced open="{" close="}"><mrow><mi>x</mi><mo>&#160;</mo><mo>&#8712;</mo><mo>&#160;</mo><mi mathvariant="normal">&#8477;</mi><mo>|</mo><mo>&#160;</mo><mi>x</mi><mo>&#62;</mo><mo>&#160;</mo><mo>-</mo><mn>2</mn></mrow></mfenced><mo>&#160;</mo><mo>=</mo><mo>&#160;</mo><mo>(</mo><mo>-</mo><mn>2</mn><mo>;</mo><mo>&#160;</mo><mo>+</mo><mo>&#8734;</mo><mo>)</mo></math></p> <p>Ta biểu diễn tập hợp D (phần m&agrave;u đỏ) như sau:</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/17062022/z3499417023974_f9d67d48c1b22214c2448f7dca51f52b-qAMoMJ.jpg" /></p>
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