|
A. 1 |
B. \(\frac12\) |
C. \(\frac14\) |
D. \(\frac18\) |
E. \(\frac1{16}\) |
[ 5-8748 - op net sinds 8.11.2022-(E)-7.11.2024 ]
Translation in E N G L I S H
|
A. 1 |
B. \(\frac12\) |
C. \(\frac14\) |
D. \(\frac18\) |
E. \(\frac1{16}\) |
Oplossing - Solution
1ste manier : zonder de regel van de l'Hospital
\( \scriptsize \quad
\scriptsize \displaystyle \lim_{x \to 1}\: \frac{ \sqrt{2\!+\!\sqrt{x+3}}-\!2}{x-1}\\
= \scriptsize \displaystyle \lim_{x \to 1}\: \frac{(\sqrt{2\!+\!\sqrt{x+3}}-\!2).
(\sqrt{2\!+\!\sqrt{x+3}}+\!2)}
{(x-1).(\sqrt{2\!+\!\sqrt{x+3}}+\!2)}\\
= \scriptsize \displaystyle \lim_{x \to 1}\: \frac {2+ \sqrt{x+3}-4}{(x-1).(\sqrt{2\!+\!\sqrt{x+3}}+\!2)}\\
= \scriptsize \displaystyle \lim_{x \to 1}\: \frac {\sqrt{x+3}-2}{(x-1).(\sqrt{2\!+\!\sqrt{x+3}}+\!2)}\\
= \scriptsize \displaystyle \lim_{x \to 1}\: \frac {x+3-4}{(x-1).(\sqrt{2\!+\!\sqrt{x+3}}+\!2).(\sqrt{x+3}+2)}\\
= \scriptsize \displaystyle \lim_{x \to 1}\: \frac {1}{(\sqrt{2\!+\!\sqrt{x+3}}+\!2).(\sqrt{x+3}+2)}\\
= \frac {1}{(2+2).(2+2)} = \frac {1}{16}
\)
2de manier : met de regel van de l'Hospital
\( \scriptsize \quad
\scriptsize \displaystyle \lim_{x \to 1}\: \frac{\sqrt{2\!+\!\sqrt{x+3}}-\!2}{x-1}\left ( =\frac 00 \right )\overset{H}{=}
\scriptsize \displaystyle \lim_{x \to 1}\: D\: \sqrt{2\!+\!\sqrt{x+3}}\\
= \scriptsize \displaystyle \lim_{x \to 1}\:\left (\frac{1}{2.\sqrt{2\!+\!\sqrt{x+3}}}.\frac{1}{2.\sqrt{x+3}}\right )=\frac{1}{2.\sqrt{2+2}}.\frac{1}{2.\sqrt 4}=\frac{1}{16}
\)