19 international practice exam ab mcq, part b - calculator required let f be the function defined above…

19 international practice exam ab mcq, part b - calculator required let f be the function defined above, where k is a positive constant. for what value of k, if any, is f continuous? a 2.081 b 2.646 c 8.550 d there is no such value of k.
Answer
Explanation:
Step1: Recall continuity condition
A function $f(x)$ is continuous at $x = a$ if $\lim_{x\rightarrow a^{-}}f(x)=\lim_{x\rightarrow a^{+}}f(x)=f(a)$. Here $a = 3$, so $\lim_{x\rightarrow3^{-}}(k^{3}+x)=\lim_{x\rightarrow3^{+}}\frac{16}{k^{2}-x}$.
Step2: Calculate left - hand limit
$\lim_{x\rightarrow3^{-}}(k^{3}+x)=k^{3}+3$.
Step3: Calculate right - hand limit
$\lim_{x\rightarrow3^{+}}\frac{16}{k^{2}-x}=\frac{16}{k^{2}-3}$.
Step4: Set up the equation
Set $k^{3}+3=\frac{16}{k^{2}-3}$. Cross - multiply to get $(k^{3}+3)(k^{2}-3)=16$. Expand the left - hand side: $k^{5}-3k^{3}+3k^{2}-9 = 16$, or $k^{5}-3k^{3}+3k^{2}-25=0$. We can try to solve this equation numerically. By using a graphing utility or a calculator with equation - solving capabilities, we find that there is no real positive value of $k$ that satisfies this equation.
Answer:
D. There is no such value of $k$.