is gelijk aan
A.   21
B.   22
C.   23
D.   24
E.   25
A    B    C    D    E

[ 5-7110 - op net sinds 16.8.12-(E)-7.11.2024 ]

Translation in   E N G L I S H



is equal to
A.  21
B.  22
C.  23
D.  24
E.  25

Oplossing - Solution

1ste manier : m.b.v. toegevoegde vormen
\(\displaystyle\lim_{x\to16}\frac{x-16}{\sqrt[4]{x}-2}=\lim_{x\to16}\frac{\left(x-16\right)\left(\sqrt[4]{x}+2\right)}{\left(\sqrt[4]{x}-2\right)\left(\sqrt[4]{x}+2\right)}=\displaystyle\lim_{x\to16}\frac{\left(x-16\right)\left(\sqrt[4]{x}+2\right)}{\left(\sqrt x-4\right)}\\=\displaystyle\lim_{x\to16}\frac{\left(x-16\right)\left(\sqrt[4]{x}+2\right)\left(\sqrt x+4\right)}{\left(\sqrt x-4\right)\left(\sqrt x+4\right)}=\lim_{x\to16}\;\left(\sqrt[4]{x}+2\right)\left(\sqrt x+4\right)\\=\left(2+2\right)\left(4+4\right)=4.8=32\)
2de manier : m.b.v. de regel van de l'Hospital
\(\displaystyle\lim_{x\to16}\frac{x-16}{\sqrt[4]{x}-2}\lim_{x\to16}\frac{x-16}{x^\frac{1}{4}-2}\left(=\frac{0}{0}\right)\buildrel H\over=\lim_{x\to16}\;\frac{1}{\frac{1}{4}x^{\frac{1}{4}-1}}=\lim_{x\to16}\;\frac{1}{\frac{1}{4}x^{-\frac{3}{4}}}\\=\displaystyle\lim_{x\to16}\;.x^\frac{3}{4}=4.16^\frac{3}{4}=4.(2^4)^\frac{3}{4}=4.2^3=4.8=32\)
GWB