Understanding the Graph of (x - 2)^2 + (y + 3)^2 = 9
The equation (x - 2)^2 + (y + 3)^2 = 9 represents a circle. To understand how to graph it, let's break down the equation and its components.
Standard Form of a Circle
The standard form of a circle's equation is:
(x - h)^2 + (y - k)^2 = r^2
Where:
- (h, k) is the center of the circle.
- r is the radius of the circle.
Analyzing the Equation
Comparing our equation (x - 2)^2 + (y + 3)^2 = 9 to the standard form, we can identify the following:
- Center: (h, k) = (2, -3)
- Radius: r^2 = 9, so r = 3
Graphing the Circle
- Locate the center: Plot the point (2, -3) on the coordinate plane.
- Draw the radius: From the center, move 3 units in all directions (up, down, left, right). This will give you four points on the circle's circumference.
- Connect the points: Draw a smooth curve connecting the four points, forming the complete circle.
Key Points
- The equation defines all points on the circle that are 3 units away from the center (2, -3).
- The square root of the constant term on the right side of the equation gives you the radius.
- The values within the parentheses (h, k) represent the opposite signs of the coordinates of the center.
By understanding the standard form of a circle equation and identifying the center and radius, you can easily graph any circle equation.