Chapter 4: Problem 64
Use the guidelines of this section to sketch the curve. In guideline D find an equation of the slant asymptote. \(y=e^{x}-x\)
Short Answer
Expert verified
The function \( e^x - x \) has a domain of all real numbers and a y-intercept at (0,1). It has no traditional slant asymptote.
Step by step solution
01
Determine the Domain
The function is given as \( y = e^x - x \). Since \( e^x \) is defined for all real numbers and \( x \) is a polynomial, the function \( y \) is defined for all real numbers. Therefore, the domain is all real numbers \( (-\infty, \infty) \).
02
Identify Intercepts
To find the y-intercept, set \( x = 0 \): \( y = e^0 - 0 = 1 \). So the y-intercept is \((0, 1)\). There is no x-intercept since \( e^x \) never equals \( x \) due to the nature of exponential growth compared to linear growth.
03
Analyze Asymptotic Behavior
For slant asymptotes (also known as oblique asymptotes), we check the end behavior as \( x \to \infty \) or \( x \to -\infty \). We will use division to determine this for large \( x \).
04
Perform Polynomial Long Division
To find slant asymptote, consider the terms by performing long division: \( \frac{e^x}{1} - x = e^x - x \). As \( x \to \infty \), \( e^x \) behaves like \( e^x \) (exponential growth) but \( -x \) becomes negligible.Divide \( e^x \) by \( x \). Approximating \( e^x \) as a constant for large values of \( x \), the significant behavior is \( y \approx e^x \).
05
Consider Slant Asymptote's Equation
Since \( e^x \) grows faster than any polynomial, when considering the linear part, for a large value of \( x \), treat \( y \approx e^x \) as exponential providing a pseudo asymptote but mainly there isn't a traditional linear slant asymptote. However, structurally no horizontal/vertical, focusing behaviors indicate the asymptotic growth of \( e^x \).
06
Conclusion
Traditionally, \( e^x - x \'s \) rate change dominates making a non-linear behavior diminishes slant concept in classic sense for described form.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Domain of a Function
The domain of a function refers to all the possible input values (usually represented by \( x \)) that can be entered into the function to produce a real output value. In the case of the function \( y = e^x - x \), both \( e^x \) and \( x \) are defined across all real numbers.
This simplicity in domain makes it versatile for solving problems and plotting graphs.
- The exponential function \( e^x \) is defined for every real number, meaning \( e^x \) never encounters division by zero or issues with square roots of negative numbers.
- The polynomial \( -x \) is also defined everywhere since subtracting \( x \) doesn't limit the input values in any way.
This simplicity in domain makes it versatile for solving problems and plotting graphs.
Y-Intercepts
Y-intercepts are points where the graph of a function crosses or touches the y-axis. To find the y-intercept of the function \( y = e^x - x \), we substitute \( x = 0 \) into the equation.
Intersections or intercepts are useful when analyzing changes in behavior between parts of a graph.
- Plugging in \( x = 0 \): \( y = e^0 - 0 = 1 \) since \( e^0 = 1 \).
- This gives us the y-intercept at the point \((0, 1)\).
Intersections or intercepts are useful when analyzing changes in behavior between parts of a graph.
Slant Asymptotes
Slant asymptotes, or oblique asymptotes, occur when the degree of the numerator of a rational function is exactly one more than the degree of the denominator.
However, in the context of \( y = e^x - x \), we're more concerned with asymptotic behavior as \( x \to \infty \).
Even though there's no clear-cut slant asymptote, considering \( e^x \) can guide understanding how drastically the graph moves upwards, far surpassing any influence the \(-x\) term might exercise. This understanding is essential for accurately sketching graphs and predicting trends.
However, in the context of \( y = e^x - x \), we're more concerned with asymptotic behavior as \( x \to \infty \).
- This function isn't a typical rational function, but understanding end behavior provides clues.
- As \( x \) grows very large, the exponential term \( e^x \) dominates \( x \)
Even though there's no clear-cut slant asymptote, considering \( e^x \) can guide understanding how drastically the graph moves upwards, far surpassing any influence the \(-x\) term might exercise. This understanding is essential for accurately sketching graphs and predicting trends.
Exponential Functions
Exponential functions, such as \( y = e^x \), feature a constant base raised to a variable exponent.
Exponential growth is extraordinarily fast compared to linear growth or even polynomial growth.
In \( y = e^x - x \), it's crucial to acknowledge the dominance of \( e^x \) as \( x \) progresses, impacting everything from sketching curves to analyzing function behavior.
Exponential growth is extraordinarily fast compared to linear growth or even polynomial growth.
- The function \( y = e^x - x \) involves an exponential term \( e^x \), contributing dynamic behavior to the graph.
- The exponential component means that as \( x \) increases, \( y \) increases rapidly and non-linearly.
In \( y = e^x - x \), it's crucial to acknowledge the dominance of \( e^x \) as \( x \) progresses, impacting everything from sketching curves to analyzing function behavior.