Math Problem Statement

Find the equation of a circle (2,3),(3,4),(-1,2)

Solution

To find the equation of a circle passing through the points (2,3)(2, 3), (3,4)(3, 4), and (1,2)(-1, 2), we can use the general equation of a circle:

x2+y2+Dx+Ey+F=0x^2 + y^2 + Dx + Ey + F = 0

where DD, EE, and FF are constants we need to determine.

Step 1: Set up the system of equations

Substitute the three points into the general equation of the circle:

For (2,3)(2, 3): (2)2+(3)2+2D+3E+F=04+9+2D+3E+F=02D+3E+F=13(2)^2 + (3)^2 + 2D + 3E + F = 0 \quad \Rightarrow \quad 4 + 9 + 2D + 3E + F = 0 \quad \Rightarrow \quad 2D + 3E + F = -13

For (3,4)(3, 4): (3)2+(4)2+3D+4E+F=09+16+3D+4E+F=03D+4E+F=25(3)^2 + (4)^2 + 3D + 4E + F = 0 \quad \Rightarrow \quad 9 + 16 + 3D + 4E + F = 0 \quad \Rightarrow \quad 3D + 4E + F = -25

For (1,2)(-1, 2): (1)2+(2)2+(1)D+2E+F=01+4D+2E+F=0D+2E+F=5(-1)^2 + (2)^2 + (-1)D + 2E + F = 0 \quad \Rightarrow \quad 1 + 4 - D + 2E + F = 0 \quad \Rightarrow \quad -D + 2E + F = -5

Step 2: Solve the system of equations

Now we have the following system of equations:

1) & \quad 2D + 3E + F = -13 \\ 2) & \quad 3D + 4E + F = -25 \\ 3) & \quad -D + 2E + F = -5 \end{aligned}$$ Let's solve this system step by step. We can solve it using elimination or substitution. I'll solve it now. The solution to the system of equations is: $$D = 2, \quad E = -14, \quad F = 25$$ ### Step 3: Write the equation of the circle Substitute $$D = 2$$, $$E = -14$$, and $$F = 25$$ into the general equation of the circle: $$x^2 + y^2 + 2x - 14y + 25 = 0$$ Thus, the equation of the circle passing through the points $$(2, 3)$$, $$(3, 4)$$, and $$(-1, 2)$$ is: $$x^2 + y^2 + 2x - 14y + 25 = 0$$ Would you like further details on any step? Here are some related questions you might find interesting: 1. How do you derive the equation of a circle from its center and radius? 2. Can a circle pass through more than three points? 3. What are the properties of the general equation of a circle? 4. How can we verify if a point lies on a given circle? 5. What happens if the three points are collinear when finding a circle? **Tip:** You can check if the points are collinear by ensuring the determinant of a matrix with these points is non-zero.

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Math Problem Analysis

Mathematical Concepts

Geometry
Equation of a Circle
Systems of Equations

Formulas

General equation of a circle: x^2 + y^2 + Dx + Ey + F = 0
System of linear equations to solve for D, E, F

Theorems

Equation of a Circle Theorem
System of Equations Solving Techniques

Suitable Grade Level

Grades 10-12