Math Problem Statement

The equation of a circle is given below. Identify the center and radius, then graph the circle. (x + 4)^2 + (y - 1)^2 = 4

Solution

To find the center and radius of the circle given by the equation:

(x+4)2+(y1)2=4(x + 4)^2 + (y - 1)^2 = 4

we need to identify it in the standard form of a circle's equation:

(xh)2+(yk)2=r2(x - h)^2 + (y - k)^2 = r^2

Step-by-Step Solution

  1. Identify the Center (h,k)(h, k):

    • In the equation (x+4)2+(y1)2=4(x + 4)^2 + (y - 1)^2 = 4, we have (x(4))2(x - (-4))^2 and (y1)2(y - 1)^2.
    • This tells us the center (h,k)(h, k) is at (4,1)(-4, 1).
  2. Find the Radius rr:

    • The right side of the equation is 4, which is r2r^2.
    • Solving for rr, we get r=4=2r = \sqrt{4} = 2.

Answer

  • Center: (4,1)(-4, 1)
  • Radius: 22

Now, to graph the circle:

  1. Plot the center at (4,1)(-4, 1).
  2. Draw a circle with a radius of 2 units from the center, ensuring it spans 2 units in all directions around the center.

Would you like further explanation on graphing or any other details?


Follow-up Questions

  1. How can you rewrite an equation to identify the center and radius of a circle?
  2. What does changing the values of hh and kk do to the position of the circle?
  3. How is the radius calculated when given an equation of a circle?
  4. What is the significance of the radius in the graph of a circle?
  5. How would you graph a circle with a center at the origin?

Tip:

When identifying the radius in a circle equation, remember that rr is the square root of the constant on the right side.

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Math Problem Analysis

Mathematical Concepts

Circle Equations
Coordinate Geometry

Formulas

(x - h)^2 + (y - k)^2 = r^2

Theorems

Equation of a Circle Theorem

Suitable Grade Level

Grades 9-10