Math Problem Statement

Find the center (h,k) and radius r of the circle and then use these to (a) graph the circle and (b) find the intercepts, if any. The given equation is: 5x^2 + 10x + 5y^2 = 0.

Solution

Let's solve the problem step by step:

Step 1: Rewrite the equation of the circle

The given equation is:

5x2+10x+5y2=05x^2 + 10x + 5y^2 = 0

Divide the entire equation by 55 to simplify:

x2+2x+y2=0x^2 + 2x + y^2 = 0

This is the simplified form of the equation.

Step 2: Complete the square to find the center and radius

To complete the square, focus on the xx-terms (x2+2xx^2 + 2x):

  1. Add and subtract (22)2=1\left(\frac{2}{2}\right)^2 = 1 to x2+2xx^2 + 2x: x2+2x=(x+1)21x^2 + 2x = (x + 1)^2 - 1

  2. Rewrite the equation with this completed square form: (x+1)21+y2=0(x + 1)^2 - 1 + y^2 = 0

  3. Simplify further: (x+1)2+y2=1(x + 1)^2 + y^2 = 1

Step 3: Identify the center and radius

The equation (x+1)2+y2=1(x + 1)^2 + y^2 = 1 represents a circle with:

  • Center (h,k)=(1,0)(h, k) = (-1, 0)
  • Radius r=1=1r = \sqrt{1} = 1

Step 4: Graph the circle

The circle has:

  • A center at (1,0)(-1, 0)
  • A radius of 11, so it will pass through points (2,0)(-2, 0), (0,0)(0, 0), (1,1)(-1, 1), and (1,1)(-1, -1).

Step 5: Find the intercepts

  1. x-intercepts: Set y=0y = 0 in (x+1)2+y2=1(x + 1)^2 + y^2 = 1: (x+1)2=1    x+1=±1(x + 1)^2 = 1 \implies x + 1 = \pm 1 Solve for xx: x=0andx=2x = 0 \quad \text{and} \quad x = -2 So the x-intercepts are (0,0)(0, 0) and (2,0)(-2, 0).

  2. y-intercepts: Set x=0x = 0 in (x+1)2+y2=1(x + 1)^2 + y^2 = 1: (0+1)2+y2=1    1+y2=1(0 + 1)^2 + y^2 = 1 \implies 1 + y^2 = 1 y2=0    y=0y^2 = 0 \implies y = 0 So the y-intercept is (0,0)(0, 0).


Final Results:

  1. Center: (1,0)(-1, 0)
  2. Radius: 11
  3. x-intercepts: (0,0)(0, 0), (2,0)(-2, 0)
  4. y-intercept: (0,0)(0, 0)

Do you want me to:

  • Graph the circle for you?
  • Provide further details on how intercepts were calculated?

Related Questions:

  1. How do you find the standard equation of a circle from general form?
  2. What are the steps to complete the square in a quadratic equation?
  3. How do intercepts of a circle relate to its radius?
  4. Can a circle's equation ever have no intercepts? Why or why not?
  5. How would this equation change if it represented an ellipse instead of a circle?

Tip: Always simplify equations first to make the process of finding intercepts and centers easier!

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Math Problem Analysis

Mathematical Concepts

Circle Equation
Completing the Square
Graphing Circles
Finding Intercepts

Formulas

Standard form of a circle: (x - h)^2 + (y - k)^2 = r^2
Completing the square formula

Theorems

Properties of Circle Equation
Intercepts of a Circle

Suitable Grade Level

Grades 10-12