limite x->2 (x^2-4)/(x-2)
Compute the limit of <math><mfrac><mrow><msup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msup><mo> -</mo><mn>4</mn></mrow><mrow><mi>x</mi><mo> -</mo><mn>2</mn></mrow></mfrac></math> as <m><math><mi>x</mi><mo> → </mo><mn>2</mn></math></m> The limit of <math><msup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msup></math> is <m><math><msup><mrow><mn>2</mn></mrow><mrow><mn>2</mn></mrow></msup></math></m> when <m><math><mi>x</mi><mo> → </mo><mn>2</mn></math></m> The limit of <math><msup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msup><mo> -</mo><mn>4</mn></math> is <m><math><mn>0</mn></math></m> when <m><math><mi>x</mi><mo> → </mo><mn>2</mn></math></m> The limit of <math><mi>x</mi><mo> -</mo><mn>2</mn></math> is <m><math><mn>0</mn></math></m> when <m><math><mi>x</mi><mo> → </mo><mn>2</mn></math></m> For <math><mfrac><mrow><msup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msup><mo> -</mo><mn>4</mn></mrow><mrow><mi>x</mi><mo> -</mo><mn>2</mn></mrow></mfrac></math>, the limit takes the <u>indeterminate form</u> <m>0/0</m> when <math><mi>x</mi></math> → <math><mn>2</mn></math> We can use L'Hôpital's rule (<m>limif of a/b = limit of a'/b'</m>) by computing the derivatives of the numerator and the denominator: Let's perform the differentiation: <math><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msup><mo> -</mo><mn>4</mn><mo>)'</mo></math> <math><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>)'</mo><mo> + </mo><mn>0</mn></math> <math><mn>2</mn><mi>x</mi></math> Let's perform the differentiation: <math><mo>(</mo><mi>x</mi><mo> -</mo><mn>2</mn><mo>)'</mo></math> <math><mn>1</mn><mo> + </mo><mn>0</mn></math> <math><mn>1</mn></math> With the derivatives of the numerator and the denominator, we obtain a new fraction whose limit can be determined: The limit of <math><mn>2</mn><mi>x</mi></math> is <m><math><mn>4</mn></math></m> when <m><math><mi>x</mi><mo> → </mo><mn>2</mn></math></m> So the limit of <math><mfrac><mrow><msup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msup><mo> -</mo><mn>4</mn></mrow><mrow><mi>x</mi><mo> -</mo><mn>2</mn></mrow></mfrac></math> is <m><math><mn>4</mn></math></m> when <m><math><mi>x</mi><mo> → </mo><mn>2</mn></math></m> ▷<b>Result: <math><mn>4</mn></math></b><span style='font-size:smaller'> (computation required 15 steps and 5 ms)</span>
