Chapter 4: Problem 53
Sketch the graph of each power function by hand, using a calculator only to evaluate \(y\)-values for your chosen \(x\) -values. On the same axes, graph \(y=x^{2}\) for comparison. In each case, \(x \geq 0\) .$$f(x)=x^{2.5}$$
Short Answer
Expert verified
Plot y-values for chosen x-values for both functions, then compare the curves. f(x)=x^{2.5} rises faster than y=x^2.
Step by step solution
01
Choose x-values
Select a range of x-values to use for plotting the graph. Since we are given that \(x \geq 0\), choose non-negative values such as 0, 1, 2, 3, and 4.
02
Calculate y-values for f(x)=x^{2.5}
Using a calculator, compute the corresponding y-values for the function \(f(x)=x^{2.5}\) with the chosen x-values. For example, calculate \(f(0)=0^{2.5}=0\), \(f(1)=1^{2.5}=1\), \(f(2)=2^{2.5}=5.657\), \(f(3)=3^{2.5}=15.588\), and \(f(4)=4^{2.5}=32\).
03
Calculate y-values for y=x^2
Similarly, for comparison, calculate the y-values for the function \(y=x^{2}\) using the same x-values. For instance, \(y(x=0)=0^{2}=0\), \(y(x=1)=1^{2}=1\), \(y(x=2)=2^{2}=4\), \(y(x=3)=3^{2}=9\), and \(y(x=4)=4^{2}=16\).
04
Plot the points for f(x)=x^{2.5}
On the graph, plot the points obtained for \(f(x)=x^{2.5}\): (0,0), (1,1), (2,5.657), (3,15.588), and (4,32). Connect these points smoothly as the curve increases exponentially.
05
Plot the points for y=x^2
On the same graph, plot the points for \(y=x^{2}\): (0,0), (1,1), (2,4), (3,9), and (4,16). Draw the quadratic curve connecting these points.
06
Compare the graphs
Compare the two curves on the graph. Notice that the curve \(f(x)=x^{2.5}\) grows faster than \(y=x^{2}\) as \(x\) increases, indicating a steeper increase as \(x\) becomes larger.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Graphing
Graphing is a visual way to represent mathematical functions on a coordinate plane. It involves plotting points and connecting them to show how one variable affects another. In this context, we are looking at power functions like \(f(x) = x^{2.5}\) and quadratic functions like \(y = x^2\).
To graph effectively, follow these steps:
To graph effectively, follow these steps:
- Choose a set of \(x\)-values: Since our constraint is \(x \geq 0\), focus on non-negative values. Common choices include 0, 1, 2, 3, and higher integers depending on the function.
- Calculate the corresponding \(y\)-values for both functions. This step is crucial as it gives you the points you will plot.
- Plot these points on the graph: For each \(x\)-value, there is a corresponding \(y\)-value for each function. Place these points accurately on your coordinate grid.
- Connect the dots smoothly: Once the points are plotted, connect them with a smooth curve. This will show the overall shape and direction of the function.
Exponents
Exponents are a way to represent repeated multiplication. In the function \(f(x) = x^{2.5}\), the term \(x^{2.5}\) means that \(x\) is raised to the power of 2.5. This is a non-integer exponent, which can be thought of as multiplying \(x\) by itself 2.5 times in a certain mathematical sense.
Understanding exponents is essential:
Understanding exponents is essential:
- Whole number exponents: \(x^2\) means \(x \times x\). It's straightforward and easy to visualize.
- Fractional exponents: These indicate roots. For example, \(x^{1/2}\) is the square root of \(x\).
- Decimal exponents: These can be tricky but follow the same principles. \(x^{2.5}\) implies \(x^2\) times \(x^{0.5}\) or \(\sqrt{x}\).
Quadratic function
Quadratic functions, represented by \(y = x^2\), are a specific type of polynomial function. They involve squaring the variable, and the graph of a quadratic function is always a parabola. This shape is symmetric about a vertical line down its center, which is known as the axis of symmetry. Understanding its properties helps in sketching accurate graphs.
- Basic shape: The simplest quadratic function, \(y = x^2\), produces a parabola opening upwards.
- Vertex: The highest or lowest point, depending on direction. For \(y = x^2\), the vertex is at (0, 0).
- Axis of symmetry: For our function, it is the line \(x = 0\) or the \(y\)-axis itself.
- Roots: These are the \(x\)-values where the function crosses the \(x\)-axis. For \(y = x^2\), the only root is \(x = 0\).