<span data-v-a7c68f28="">Hướng dẫn giải Hoạt động 3 (Trang 52 SGK Toán Giải Tích 12)</span>
<p><strong>Đề bài</strong></p>
<p>Chứng minh tính chất: <math xmlns="http://www.w3.org/1998/Math/MathML"><mroot><mi>a</mi><mi>n</mi></mroot><mo>.</mo><mroot><mi>b</mi><mi>n</mi></mroot><mo>=</mo><mroot><mrow><mi>a</mi><mi>b</mi></mrow><mi>n</mi></mroot></math></p>
<p><strong>Lời giải chi tiết</strong></p>
<p>Đặt <math xmlns="http://www.w3.org/1998/Math/MathML"><mroot><mi>a</mi><mi>n</mi></mroot><mo>=</mo><mi>x</mi><mo>,</mo><mo> </mo><mroot><mi>b</mi><mi>n</mi></mroot><mo>=</mo><mi>y</mi><mo>.</mo></math><br />Theo định nghĩa về căn bậc n ta có: <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>x</mi><mi>n</mi></msup><mo>=</mo><mi>a</mi><mo>,</mo><mo> </mo><msup><mi>y</mi><mi>n</mi></msup><mo>=</mo><mi>b</mi><mo>.</mo></math></p>
<p><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>a</mi><mo>.</mo><mi>b</mi><mo>=</mo><msup><mi>x</mi><mi>n</mi></msup><mo>.</mo><msup><mi>y</mi><mi>n</mi></msup><mo>=</mo><msup><mfenced><mrow><mi>x</mi><mi>y</mi></mrow></mfenced><mi>n</mi></msup></math></p>
<p>Vậy xy là căn bậc n của ab</p>
<p>Hay <math xmlns="http://www.w3.org/1998/Math/MathML"><mroot><mrow><mi>a</mi><mi>b</mi></mrow><mi>n</mi></mroot><mo>=</mo><mi>x</mi><mi>y</mi><mo>=</mo><mroot><mi>a</mi><mi>n</mi></mroot><mo>.</mo><mroot><mi>b</mi><mi>n</mi></mroot></math>.</p>