Question

Write method distance to calculate the distance between two points \((x I, y I)\) and \((x 2, y 2)\) All numbers and return values should be of type double. Incorporate this method into an application that enables the user to enter the coordinates of the points.

Short answer

Use the distance formula and create a method to calculate it; integrate user input to test.

Step-by-step solution

Understand the Distance Formula

The distance between two points \( (x_1, y_1) \) and \( (x_2, y_2) \) in a 2D plane can be calculated using the distance formula: \(\text{Distance} = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}\). This formula is derived from the Pythagorean theorem.

Create Method Signature

Since the method needs to calculate distance using doubles, define the method in Java as follows: ```java public static double distance(double x1, double y1, double x2, double y2) ``` This method will return the calculated distance.

Implement Distance Calculation

Inside the method, implement the calculation using the distance formula: ```java public static double distance(double x1, double y1, double x2, double y2) { return Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2)); } ```

Integrate with User Input

Set up the main application to receive input from the user. Create a scanner object to read user input: ```java Scanner scanner = new Scanner(System.in); ``` Prompt user to enter coordinates and store them: ```java System.out.println("Enter x1, y1, x2, y2:"); double x1 = scanner.nextDouble(); double y1 = scanner.nextDouble(); double x2 = scanner.nextDouble(); double y2 = scanner.nextDouble(); ```

Calculate and Display Result

Use the distance method to calculate the distance between the given points: ```java double dist = distance(x1, y1, x2, y2); System.out.println("The distance is: " + dist); ``` Close the scanner after use to prevent resource leaks: ```java scanner.close(); ```

Key concepts

Distance Calculation

Understanding how to calculate the distance between two points in a 2D space is a fundamental concept in geometry and programming. The distance formula, \[ \text{Distance} = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} \] is derived from the Pythagorean theorem and is used widely. When you apply this formula, you get the shortest path between the two points on a flat plane. In programming, this involves taking the square of the difference between the x-coordinates and adding it to the square of the difference between the y-coordinates. Finally, you take the square root of the result. This result gives you the linear distance.

2D Coordinate Geometry

2D coordinate geometry deals with the representation of geometric figures in a two-dimensional plane, defined by the x and y axes. Each point is characterized by a pair of coordinates \((x, y)\).Points are the basic elements here, and their relationships, such as distance and alignment, can be analyzed using mathematical formulas. In this context, understanding the positioning and movement of points is crucial for programming tasks involving graphics, simulations, and spatial analysis. Calculating distances is one of the many operations you'll perform in this realm, and mastering it offers a solid foundation for more complex geometric operations.

Method Implementation

Implementing a method in Java requires setting up a clear definition of what the function will do, what parameters it will take, and what it will return. In the example of a distance calculation, the Java method should be designed clearly to accept four double parameters: \((x_1, y_1, x_2, y_2)\). The method's signature is ```java public static double distance(double x1, double y1, double x2, double y2)```which indicates the method is static, returns a double type, and inputs four double parameters. Inside the method, the logic for computing distance follows exactly what you derived in the distance formula. The use of Math functions like \(Math.sqrt\) and \(Math.pow\) simplifies complex calculations and ensures precision.

User Input Handling

Handling user input is an essential part of interactive applications. In Java, the `Scanner` class is a convenient way to obtain user input. First, you create a scanner object: ```java Scanner scanner = new Scanner(System.in);```Once the scanner is set up, take input from the user by prompting them to enter the values for \(x_1, y_1, x_2,\) and \(y_2\). For each value, use appropriate methods like `nextDouble()` to parse the input as a double data type. Be sure to validate these inputs in real-world applications to handle exceptions or incorrect input effectively. Once all inputs are gathered, call the method to compute the distance, and print the result. Remember, it's good practice to close the scanner object once you're done to free up system resources: ```java scanner.close();```