Evaluate the limits.

[tex]\[
f(x)=\left\{\begin{array}{ll}
8x^2 - 10x + 5 & \text{if } x \ \textless \ 0 \\
-3\sin x & \text{if } x \geq 0
\end{array}\right.
\][/tex]

Enter DNE if the limit does not exist.

[tex]\[
\begin{array}{l}
\lim_{x \rightarrow 0^{-}} f(x) = \square \\
\lim_{x \rightarrow 0^{+}} f(x) = \square \\
\lim_{x \rightarrow 0} f(x) = \square
\end{array}
\][/tex]



Answer :

Let's carefully evaluate the given piecewise function:
[tex]\[ f(x) = \begin{cases} 8x^2 - 10x + 5 & \text{if } x < 0 \\ -3 \sin(x) & \text{if } x \geq 0 \end{cases} \][/tex]

We need to find the following limits:

1. [tex]\(\lim_{x \to 0^-} f(x)\)[/tex]
2. [tex]\(\lim_{x \to 0^+} f(x)\)[/tex]
3. [tex]\(\lim_{x \to 0} f(x)\)[/tex]

Step 1: Evaluate [tex]\(\lim_{x \to 0^-} f(x)\)[/tex]

For [tex]\( x < 0 \)[/tex], the function [tex]\( f(x) \)[/tex] is given by [tex]\( 8x^2 - 10x + 5 \)[/tex].

We need to find the limit of this expression as [tex]\( x \)[/tex] approaches [tex]\( 0 \)[/tex] from the left:
[tex]\[ \lim_{x \to 0^-} (8x^2 - 10x + 5) \][/tex]

Since this is a polynomial, we can substitute [tex]\( x = 0 \)[/tex] directly into the expression:
[tex]\[ 8(0)^2 - 10(0) + 5 = 5 \][/tex]

So,
[tex]\[ \lim_{x \to 0^-} f(x) = 5 \][/tex]

Step 2: Evaluate [tex]\(\lim_{x \to 0^+} f(x)\)[/tex]

For [tex]\( x \geq 0 \)[/tex], the function [tex]\( f(x) \)[/tex] is given by [tex]\( -3 \sin(x) \)[/tex].

We need to find the limit of this expression as [tex]\( x \)[/tex] approaches [tex]\( 0 \)[/tex] from the right:
[tex]\[ \lim_{x \to 0^+} (-3 \sin(x)) \][/tex]

Since [tex]\(\sin(x)\)[/tex] is continuous and [tex]\(\sin(0) = 0\)[/tex], we have:
[tex]\[ -3 \sin(0) = -3 \cdot 0 = 0 \][/tex]

So,
[tex]\[ \lim_{x \to 0^+} f(x) = 0 \][/tex]

Step 3: Evaluate [tex]\(\lim_{x \to 0} f(x)\)[/tex]

Now, we compare the left-hand limit and the right-hand limit as [tex]\( x \)[/tex] approaches [tex]\( 0 \)[/tex].

From Step 1:
[tex]\[ \lim_{x \to 0^-} f(x) = 5 \][/tex]

From Step 2:
[tex]\[ \lim_{x \to 0^+} f(x) = 0 \][/tex]

Since the left-hand limit and the right-hand limit are not equal, the overall limit [tex]\(\lim_{x \to 0} f(x)\)[/tex] does not exist.

Thus:
[tex]\[ \lim_{x \to 0} f(x) = \text{DNE (Does Not Exist)} \][/tex]

Summary:

[tex]\[ \lim_{x \rightarrow 0^{-}} f(x)= 5 \\ \lim_{x \rightarrow 0^{+}} f(x)= 0 \\ \lim_{x \rightarrow 0} f(x)= \text{DNE} \][/tex]