Math Problem Statement

X^2+y^2+4x-14y+45=0 find the general equation to standard equation

Solution

To convert the given general equation of a circle into its standard form, we need to complete the square for both the xx and yy terms.

Given equation:

x2+y2+4x14y+45=0x^2 + y^2 + 4x - 14y + 45 = 0

Steps to convert it to the standard form:

  1. Group the xx terms together and the yy terms together: (x2+4x)+(y214y)=45(x^2 + 4x) + (y^2 - 14y) = -45

  2. Complete the square for both xx and yy terms:

    • For x2+4xx^2 + 4x:
      • Take half of the coefficient of xx, which is 4, and then square it: (42)2=4\left(\frac{4}{2}\right)^2 = 4.
      • Add and subtract this value within the equation: (x2+4x+44)(x^2 + 4x + 4 - 4)
    • For y214yy^2 - 14y:
      • Take half of the coefficient of yy, which is -14, and then square it: (142)2=49\left(\frac{-14}{2}\right)^2 = 49.
      • Add and subtract this value within the equation: (y214y+4949)(y^2 - 14y + 49 - 49)

    Now, the equation becomes: (x2+4x+4)+(y214y+49)449=45(x^2 + 4x + 4) + (y^2 - 14y + 49) - 4 - 49 = -45

  3. Rewrite the equation with perfect squares: (x+2)2+(y7)253=45(x + 2)^2 + (y - 7)^2 - 53 = -45

  4. Simplify the equation by adding 53 to both sides: (x+2)2+(y7)2=8(x + 2)^2 + (y - 7)^2 = 8

Standard form of the equation:

(x+2)2+(y7)2=8(x + 2)^2 + (y - 7)^2 = 8

This is the standard form of the given circle equation, where the center of the circle is at (2,7)(-2, 7) and the radius is 8\sqrt{8}.


Would you like any more details or have any questions?

Here are some related questions:

  1. How do you determine the center and radius of a circle from its standard equation?
  2. What is the geometric interpretation of completing the square?
  3. How do you find the equation of a circle given its center and radius?
  4. What changes occur if the equation was a parabola instead of a circle?
  5. Can the standard form equation be used to graph the circle? How?
  6. What happens if the constant on the right side of the standard form is negative?
  7. How does the equation change if the circle is translated?
  8. How does this method apply to ellipses and hyperbolas?

Tip: Always check the signs when completing the square to ensure accuracy in finding the standard form.