Questions: Suppose that the function (f) is defined, for all real numbers, as follows.
[
f(x)=leftbeginarraycc
-5 x+3 text if x leq 2
x-4 text if x>2
endarrayright.
]
Graph the function (f). Then determine whether or not the function is continuous.
Is the function continuous?
Yes
No
Transcript text: Suppose that the function $f$ is defined, for all real numbers, as follows.
\[
f(x)=\left\{\begin{array}{cc}
-5 x+3 & \text { if } x \leq 2 \\
x-4 & \text { if } x>2
\end{array}\right.
\]
Graph the function $f$. Then determine whether or not the function is continuous.
Is the function continuous?
Yes
No
Solution
Solution Steps
Step 1: Define the Piecewise Function
The function \( f(x) \) is defined as:
\[ f(x) = \begin{cases}
-5x + 3 & \text{if } x \leq 2 \\
x - 4 & \text{if } x > 2
\end{cases} \]
Step 2: Graph the Function for \( x \leq 2 \)
For \( x \leq 2 \), the function is \( f(x) = -5x + 3 \).
When \( x = 2 \), \( f(2) = -5(2) + 3 = -10 + 3 = -7 \).
When \( x = 0 \), \( f(0) = -5(0) + 3 = 3 \).
Plot the points (2, -7) and (0, 3) and draw the line segment for \( x \leq 2 \).
Step 3: Graph the Function for \( x > 2 \)
For \( x > 2 \), the function is \( f(x) = x - 4 \).
When \( x = 3 \), \( f(3) = 3 - 4 = -1 \).
When \( x = 4 \), \( f(4) = 4 - 4 = 0 \).
Plot the points (3, -1) and (4, 0) and draw the line segment for \( x > 2 \).
Step 4: Check Continuity at \( x = 2 \)
To determine if the function is continuous at \( x = 2 \), check the following:
The left-hand limit as \( x \) approaches 2 from the left: \( \lim_{{x \to 2^-}} f(x) = -5(2) + 3 = -7 \).
The right-hand limit as \( x \) approaches 2 from the right: \( \lim_{{x \to 2^+}} f(x) = 2 - 4 = -2 \).
The value of the function at \( x = 2 \): \( f(2) = -7 \).
Since the left-hand limit (\(-7\)) does not equal the right-hand limit (\(-2\)), the function is not continuous at \( x = 2 \).