Questions: Let f be defined by
f(x)=
4x+m, x<2
-6x^2+2m, x >= 2
(a) Find (in terms of m ): lim x->2+ f(x)=2m-24
(b) Find (in terms of m ): lim x->2- f(x)=m+8
(c) Find all values of m such that
lim x->2- f(x)=lim x->2+ f(x)
Values of m=
DNE
Transcript text: Let $f$ be defined by
\[
f(x)=\left\{\begin{array}{ll}
4 x+m, & x<2 \\
-6 x^{2}+2 m, & x \geq 2
\end{array}\right.
\]
(a) Find (in terms of $m$ ): $\lim _{x \rightarrow 2^{+}} f(x)=2 m-24$
(b) Find (in terms of $m$ ): $\lim _{x \rightarrow 2^{-}} f(x)=m+8$
(c) Find all values of $m$ such that
\[
\lim _{x \rightarrow 2^{-}} f(x)=\lim _{x \rightarrow 2^{+}} f(x)
\]
(Note: if there are more than one such value, list them separated by commas)
\[
\text { Values of } m=
\]
$\square$ DNE
Solution
Solution Steps
Step 1: Find \(\lim _{x \rightarrow 2^{+}} f(x)\)
For \(x \geq 2\), the function is defined as \(f(x) = -6x^{2} + 2m\). To find \(\lim _{x \rightarrow 2^{+}} f(x)\), substitute \(x = 2\) into the expression:
\[
\lim _{x \rightarrow 2^{+}} f(x) = -6(2)^{2} + 2m = -24 + 2m.
\]
Step 2: Find \(\lim _{x \rightarrow 2^{-}} f(x)\)
For \(x < 2\), the function is defined as \(f(x) = 4x + m\). To find \(\lim _{x \rightarrow 2^{-}} f(x)\), substitute \(x = 2\) into the expression:
\[
\lim _{x \rightarrow 2^{-}} f(x) = 4(2) + m = 8 + m.
\]
Step 3: Set the limits equal and solve for \(m\)
For the limits to be equal, we set \(\lim _{x \rightarrow 2^{-}} f(x) = \lim _{x \rightarrow 2^{+}} f(x)\):
\[
8 + m = -24 + 2m.
\]
Subtract \(m\) from both sides:
\[
8 = -24 + m.
\]
Add \(24\) to both sides:
\[
m = 32.
\]
Thus, the value of \(m\) that satisfies the condition is \(m = 32\).