Chapter 4: Problem 23
Sketch the graph of the function using the approach presented in this section. $$f(x)=\frac{x}{(x+3)^{2}}$$
Short Answer
Expert verified
The graph of \(f(x)=\frac{x}{(x+3)^{2}}\) has a vertical asymptote at \(x = -3\), an x-intercept at \(x = 0\), and a y-intercept at \(y = 0\). The graph approaches but does not touch the vertical asymptote at \(x = -3\).
Step by step solution
01
Determine the Domain
The denominator of a fraction cannot be equal to zero because division by zero is undefined. Thus, to find the domain of \(f(x)=\frac{x}{(x+3)^{2}}\), set the denominator equal to zero and solve for x: \((x+3)^{2} = 0\). Solve this to find \(x= -3\). So, the domain of the function is \(x \in R, x ≠-3\).
02
Determine the Vertical Asymptote
A vertical asymptote occurs at the values of x where the function is undefined. From step 1, we know that x cannot be -3, so x = -3 is the vertical asymptote.
03
Determine the x-intercept
The x-intercept of the graph of a function is the value of x when the function is equal to 0. So, set the function equal to zero and solve for x: \(\frac{x}{(x+3)^{2}} = 0\). The solution is \(x=0\). Therefore, the x-intercept is at x=0.
04
Determine the y-intercept
The y-intercept of the graph of a function is the y value when x = 0. Substitute 0 into the function to get the y value: \(f(0) =\frac{0}{(0+3)^{2}} = 0\). So the y-intercept is at y = 0.
05
Sketch the graph
We can now sketch the graph using the information we have. The graph has a vertical asymptote at \(x = -3\), an x-intercept at \(x = 0\) and a y-intercept at \(y = 0\). The shape of the graph can be determined by looking at the general form of the function, which is a rational function. The graph will approach the vertical asymptote but never touch it. Draw the graph accordingly adjusting based on these features.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Domain of a Function
When finding the domain of a function, especially for rational functions, it is essential to spot any values that make the denominator zero. For the function \( f(x) = \frac{x}{(x+3)^2} \), identify the values of \(x\) that would result in division by zero since this is undefined in mathematics.
- Set the denominator \((x+3)^2\) equal to zero.
- Solve the equation to find \(x = -3\).
Vertical Asymptote
Vertical asymptotes are lines that a graph approaches but never actually touches or crosses. They occur in rational functions at points where the function is undefined due to a zero in the denominator. For \( f(x) = \frac{x}{(x+3)^2} \), as identified in the domain, there is a vertical asymptote at \( x = -3 \).
- As \(x\) gets closer to \(-3\), the value of the function grows infinitely large or small in magnitude.
- The graph will approach, but never intersect this vertical line.
X-Intercept
Finding the x-intercept involves setting the entire function equal to zero and solving for \(x\). With our function \( f(x) = \frac{x}{(x+3)^2} \), note that only the numerator can be zero for the whole fraction to equal zero.
- Set \(x = 0\) because the numerator \(x\) must be zero.
- So, the x-intercept is at the point \(x=0\).
Y-Intercept
To find the y-intercept, substitute \( x = 0 \) into the function and simplify the expression. For \( f(x) = \frac{x}{(x+3)^2} \), when \( x = 0 \), it results in:
- \( f(0) = \frac{0}{(0+3)^2} = 0 \).
- Therefore, the y-intercept is at \( y = 0 \).
Rational Functions
Rational functions are ratios of two polynomials, written in the form \( \frac{f(x)}{g(x)} \). These functions, like \( f(x) = \frac{x}{(x+3)^2} \), are important as they can exhibit interesting behavior like vertical asymptotes, intercepts, and horizontal asymptotes.
- The behavior of rational functions often involves creating vertical asymptotes where the denominator is zero.
- These functions can have various shapes: simple lines, curves, or complex shapes depending on the degrees of the numerator and denominator.