Problem 25 - Intermediate Algebra

Question

Graph each function. $$ f(x)=e^{x} $$

Step-by-Step Solution

Answer

The function \(f(x) = e^x\) is an increasing exponential curve passing through \((0, 1)\), with the x-axis as a horizontal asymptote.

Step 1: Recognize the Function Type

The function given is the exponential function \(f(x) = e^x\). This is a continuous and smooth curve that is always increasing for all \(x\) values.

Step 2: Identify the Basic Characteristics

For the function \(f(x) = e^x\), it passes through the point \((0, 1)\) because \(e^0 = 1\). The asymptotic behavior is such that as \(x\) approaches negative infinity, \(f(x)\) approaches 0, but never touches the x-axis.

Step 3: Plot Key Points

Calculate and plot a few key points to guide the graphing:- \(x = -1\): \(f(-1) = e^{-1} \approx 0.37\)- \(x = 0\): \(f(0) = e^0 = 1\)- \(x = 1\): \(f(1) = e^1 \approx 2.72\)

Step 4: Sketch the Graph

Using the points plotted, sketch the curve. The graph starts near the x-axis for negative \(x\) values, passes through the point \((0, 1)\), and rises steeply as \(x\) increases.

Step 5: Describe Graph Behavior

The graph of \(f(x) = e^x\) shows exponential growth. It increases rapidly after passing through \((0, 1)\), reflecting the nature of exponential functions.

Key Concepts

Exponential Growth

Exponential growth is a concept where quantities increase rapidly as they build upon themselves. In the case of the function \( f(x) = e^x \), this is demonstrated very clearly.
At the heart of exponential growth is the idea of compounding. When the function's input \( x \) increases, the output \( f(x) \), or the y-value, climbs swiftly because it is continually multiplied by the base, which is the number \( e \) here.
This characteristic of exponential growth is why even small changes in \( x \) can lead to significant increases in \( f(x) \).

• For \( x = 0 \), \( f(x) = e^0 = 1 \).
• For \( x = 1 \), \( f(x) = e^1 \approx 2.72 \).
• For \( x = 2 \), \( f(x) = e^2 \approx 7.39 \).

As you can see, with each unit increase in \( x \), the value of \( f(x) \) grows significantly larger. This is the inherently steep climb characteristic of exponential growth, which is widely seen in models of population growth, financial investments, and certain natural processes.

Asymptotic Behavior

Asymptotic behavior is a vital feature when discussing the graph of an exponential function. For \( f(x) = e^x \), one of the key aspects is that as \( x \) moves toward negative infinity, the value of \( f(x) \) nears zero, but never actually reaches zero.
This means the curve approaches the x-axis ut does not cross or touch it.
The line \( y = 0 \) serves as a horizontal asymptote for this curve.

• When \( x = -1 \), \( f(x) = e^{-1} \approx 0.37 \).
• As \( x \) becomes a larger negative number, \( f(x) \) continues to get closer to 0.

This behavior remains constant no matter how negative \( x \) becomes, as \( e^x \) continues to shrink by way of a fractionally smaller term while never quite reaching zero. This is what creates the 'tail' that flattens out alongside the x-axis.

Key Points in a Graph

Identifying key points on the graph of an exponential function such as \( f(x) = e^x \) is crucial for accurately depicting its shape and behavior. Key points help guide and ensure an accurate sketch. Typically, finding a few strategic points can help effectively outline an entire exponential curve.
Let's take a look at some key points:

• The Y-Intercept: For \( f(x) = e^x \), it is at the point \( (0, 1) \). This happens because when \( x = 0 \), \( e^0 = 1 \).
• A Point Near the Y-Intercept: For instance, \( x = 1 \), gives \( f(1) = e^1 \approx 2.72 \), portraying the immediate rise.
• A Point for Negative Values: For example, \( x = -1 \) yields \( f(-1) = e^{-1} \approx 0.37 \).

By plotting these simple but crucial points, you can begin to sketch the exponential curve. These points translate smoothly into a continuous line that reflects the exponential growth from negative to positive infinity, anchoring through these positions.