Verified Answer :
- Identify the vertex from the form \(h(x) = (x - h)^2 + k\) as \((2, 3)\).
- Determine that the parabola opens upwards because the lead coefficient is positive.
- Calculate key points including the y-intercept \((0, 7)\) and points \((1, 4)\), \((3, 4)\), and \((4, 7)\) to guide the sketch.
- Sketch the curve on a coordinate plane, ensuring it is a smooth, symmetric, U-shaped parabola.
Explanation
- Analyzing the Function and Identifying the Vertex
The function \(h(x) = (x - 2)^2 + 3\) is a quadratic function given in vertex form, \(h(x) = a(x - h)^2 + k\), where \((h, k)\) represents the vertex of the parabola. By comparing the given expression, we identify \(h = 2\) and \(k = 3\). Therefore, the vertex of this parabola is at the point \((2, 3)\). The coefficient \(a = 1\) is positive, which indicates that the parabola opens upwards.
- Determining the Axis of Symmetry and Intercepts
The axis of symmetry for a parabola in vertex form is the vertical line passing through the vertex, which is \(x = h = 2\). To further define the shape, we calculate the y-intercept by evaluating the function at \(x = 0\):
\[h(0) = (0 - 2)^2 + 3 = (-2)^2 + 3 = 4 + 3 = 7.\]
So, the y-intercept is at the point \((0, 7)\). Due to the symmetry of the parabola about the line \(x = 2\), the point symmetric to \((0, 7)\) is \((4, 7)\).
- Calculating Additional Points for Graphing
To ensure accuracy when sketching the graph, we calculate a few more points around the vertex. For \(x = 1\):
\[h(1) = (1 - 2)^2 + 3 = (-1)^2 + 3 = 1 + 3 = 4.\]
By symmetry, at \(x = 3\), we also have \(h(3) = 4\). Thus, we have the points \((1, 4)\) and \((3, 4)\). We now have a set of points to guide our drawing: \((2, 3)\), \((0, 7)\), \((1, 4)\), \((3, 4)\), and \((4, 7)\).
- Sketching the Graph
To graph the function, start by drawing a Cartesian coordinate system with appropriate scales for both the x and y axes. Plot the vertex at \((2, 3)\) and the calculated points \((0, 7)\), \((1, 4)\), \((3, 4)\), and \((4, 7)\). Finally, draw a smooth, continuous, U-shaped curve passing through these points, making sure the curve is symmetric about the vertical line \(x = 2\). The resulting graph is a parabola opening upwards with its minimum value at the vertex \((2, 3)\).
Examples
Quadratic functions are used in various real-life scenarios, such as modeling the trajectory of a ball thrown into the air or the path of a projectile. If a person throws a basketball, its height over time can be represented by a quadratic function, similar to the one we just graphed. Understanding how to find the vertex helps in determining the maximum height the ball reaches, while other points help track the ball's position throughout its motion, assisting in sports analytics or physics simulations.