Understanding the Function
The function f(x) = (x + 2)2 – 3 is a quadratic function, which means its graph will be a parabola. The general form of a quadratic function is f(x) = ax2 + bx + c, where a, b, and c are constants. In this case, the function can be rewritten as f(x) = (x + 2)2 – 3 = x2 + 4x + 4 – 3 = x2 + 4x + 1. To understand the graph of this function, we need to analyze the coefficients of the quadratic function. The coefficient of x2 (a) determines the direction of the parabola's opening, while the coefficient of x (b) affects the parabola's symmetry. In this case, a = 1 and b = 4.Graphing the Function
To graph the function, we need to identify the key features of the parabola. The vertex of the parabola is the lowest or highest point on the graph, and it can be found using the formula x = -b/2a. In this case, x = -4/2(1) = -2. The y-coordinate of the vertex can be found by substituting the x-value into the function. Plugging in x = -2, we get y = (-2 + 2)2 – 3 = 0 – 3 = -3. Therefore, the vertex of the parabola is (-2, -3). Now that we have the vertex, we can plot the parabola. Since the parabola opens upward (a > 0), the graph will have a minimum point at the vertex. We can use this information to plot the parabola and determine which graph represents the given function.Comparing Graphs
| Function | Vertex | Axis of Symmetry | Direction of Parabola's Opening |
|---|---|---|---|
| f(x) = x2 | (0, 0) | x = 0 | Opens upward |
| f(x) = (x + 2)2 – 3 | (-2, -3) | x = -2 | Opens upward |
| f(x) = (x - 1)2 + 2 | (1, 2) | x = 1 | Opens upward |
| f(x) = (x + 3)2 – 2 | (-3, -2) | x = -3 | Opens upward |
Key Takeaways
- Identify the key features of the parabola, including the vertex and axis of symmetry.
- Use the formula x = -b/2a to find the x-coordinate of the vertex.
- Substitute the x-value into the function to find the y-coordinate of the vertex.
- Plot the parabola using the vertex and axis of symmetry.
- Compare the graph with other quadratic functions to identify key features.