Bài 2. Quy tắc tính đạo hàm
Hướng dẫn giải Hoạt động 4 (Trang 159 SGK Toán Đại số & Giải tích 11)
<p><strong class="content_question">Đề b&agrave;i</strong></p> <p>&Aacute;p dụng c&aacute;c c&ocirc;ng thức trong Định l&iacute; 3, h&atilde;y t&iacute;nh đạo h&agrave;m của c&aacute;c h&agrave;m số <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>y</mi><mo>=</mo><mn>5</mn><msup><mi>x</mi><mn>3</mn></msup><mo>-</mo><mn>2</mn><msup><mi>x</mi><mn>5</mn></msup></math>; <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>y</mi><mo>=</mo><mo>-</mo><msup><mi>x</mi><mn>3</mn></msup><msqrt><mi>x</mi></msqrt></math>.</p> <p class="content_method_header"><strong class="content_method">Phương ph&aacute;p giải</strong></p> <div class="content_method_content"> <p>Sử dụng c&aacute;c c&ocirc;ng thức t&iacute;nh đạo h&agrave;m h&agrave;m <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>y</mi><mo>=</mo><msup><mi>x</mi><mi>n</mi></msup></math>&nbsp;v&agrave; h&agrave;m&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>y</mi><mo>=</mo><msqrt><mi>x</mi></msqrt></math></p> </div> <p><strong class="content_detail">Lời giải chi tiết</strong></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mfenced><mn>1</mn></mfenced><mo>&#160;</mo><mo>&#160;</mo><mi>y</mi><mo>'</mo><mo>=</mo><mfenced><mrow><mn>5</mn><msup><mi>x</mi><mn>3</mn></msup><mo>-</mo><mn>2</mn><msup><mi>x</mi><mn>5</mn></msup></mrow></mfenced><mo>'</mo><mo>=</mo><mfenced><mrow><mn>5</mn><msup><mi>x</mi><mn>3</mn></msup></mrow></mfenced><mo>'</mo><mo>-</mo><mfenced><mrow><mn>2</mn><msup><mi>x</mi><mn>5</mn></msup></mrow></mfenced><mo>'</mo><mspace linebreak="newline"/><mo>=</mo><mfenced><mrow><mn>5</mn><mo>'</mo><mo>.</mo><msup><mi>x</mi><mn>3</mn></msup><mo>+</mo><mn>5</mn><mo>(</mo><msup><mi>x</mi><mn>3</mn></msup><mo>)</mo><mo>'</mo></mrow></mfenced><mo>-</mo><mfenced><mrow><mn>2</mn><mo>'</mo><mo>.</mo><msup><mi>x</mi><mn>5</mn></msup><mo>+</mo><mn>2</mn><mo>(</mo><msup><mi>x</mi><mn>5</mn></msup><mo>)</mo><mo>'</mo></mrow></mfenced><mspace linebreak="newline"/><mo>=</mo><mfenced><mrow><mn>0</mn><mo>.</mo><msup><mi>x</mi><mn>3</mn></msup><mo>+</mo><mn>5</mn><mo>.</mo><mn>3</mn><msup><mi>x</mi><mn>2</mn></msup></mrow></mfenced><mo>-</mo><mfenced><mrow><mn>0</mn><mo>.</mo><msup><mi>x</mi><mn>5</mn></msup><mo>+</mo><mn>2</mn><mo>.</mo><mn>5</mn><msup><mi>x</mi><mn>4</mn></msup></mrow></mfenced><mspace linebreak="newline"/><mo>=</mo><mfenced><mrow><mn>0</mn><mo>+</mo><mn>15</mn><msup><mi>x</mi><mn>2</mn></msup></mrow></mfenced><mo>-</mo><mfenced><mrow><mn>0</mn><mo>+</mo><mn>10</mn><msup><mi>x</mi><mn>4</mn></msup></mrow></mfenced><mspace linebreak="newline"/><mo>=</mo><mn>15</mn><msup><mi>x</mi><mn>2</mn></msup><mo>-</mo><mn>10</mn><msup><mi>x</mi><mn>4</mn></msup></math></p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><mfenced><mn>2</mn></mfenced><mo>&#160;</mo><mo>&#160;</mo><mi>y</mi><mo>'</mo><mo>=</mo><mfenced><mrow><mo>-</mo><msup><mi>x</mi><mn>3</mn></msup><msqrt><mi>x</mi></msqrt></mrow></mfenced><mo>'</mo><mspace linebreak="newline"/><mo>=</mo><mfenced><mrow><mo>-</mo><msup><mi>x</mi><mn>3</mn></msup></mrow></mfenced><mo>'</mo><mo>.</mo><msqrt><mi>x</mi></msqrt><mo>+</mo><mfenced><mrow><mo>-</mo><msup><mi>x</mi><mn>3</mn></msup></mrow></mfenced><mo>.</mo><mfenced><msqrt><mi>x</mi></msqrt></mfenced><mo>'</mo><mspace linebreak="newline"/><mo>=</mo><mo>-</mo><mn>3</mn><msup><mi>x</mi><mn>2</mn></msup><mo>.</mo><msqrt><mi>x</mi></msqrt><mo>-</mo><msup><mi>x</mi><mn>3</mn></msup><mo>.</mo><mfrac><mn>1</mn><mrow><mn>2</mn><msqrt><mi>x</mi></msqrt></mrow></mfrac></math></p>
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