Math Problem Statement

Find a point on the y-axis that is equidistant from the points (8, −8) and (3, 3).

Solution

To find a point on the y-axis that is equidistant from the points (8,8)(8, -8) and (3,3)(3, 3), we need to determine the coordinates of the point on the y-axis, which will have the form (0,y)(0, y).

Step 1: Use the distance formula

The distance between two points (x1,y1)(x_1, y_1) and (x2,y2)(x_2, y_2) is given by the distance formula:

d=(x2x1)2+(y2y1)2d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}

Step 2: Set up two distance equations

Let the point on the y-axis be (0,y)(0, y).

  • The distance between (0,y)(0, y) and (8,8)(8, -8) is: d1=(08)2+(y(8))2=82+(y+8)2=64+(y+8)2d_1 = \sqrt{(0 - 8)^2 + (y - (-8))^2} = \sqrt{8^2 + (y + 8)^2} = \sqrt{64 + (y + 8)^2}

  • The distance between (0,y)(0, y) and (3,3)(3, 3) is: d2=(03)2+(y3)2=32+(y3)2=9+(y3)2d_2 = \sqrt{(0 - 3)^2 + (y - 3)^2} = \sqrt{3^2 + (y - 3)^2} = \sqrt{9 + (y - 3)^2}

Since the point on the y-axis is equidistant from both (8,8)(8, -8) and (3,3)(3, 3), we set d1=d2d_1 = d_2.

Step 3: Set up the equation

64+(y+8)2=9+(y3)2\sqrt{64 + (y + 8)^2} = \sqrt{9 + (y - 3)^2}

Step 4: Square both sides

Squaring both sides of the equation to eliminate the square roots:

64+(y+8)2=9+(y3)264 + (y + 8)^2 = 9 + (y - 3)^2

Step 5: Expand both sides

Expand the squares on both sides:

64+(y2+16y+64)=9+(y26y+9)64 + (y^2 + 16y + 64) = 9 + (y^2 - 6y + 9)

Simplifying:

128+y2+16y=y26y+18128 + y^2 + 16y = y^2 - 6y + 18

Step 6: Eliminate y2y^2 and simplify

Since y2y^2 appears on both sides, we can subtract it from both sides:

128+16y=6y+18128 + 16y = -6y + 18

Now, combine like terms:

128+16y+6y=18128 + 16y + 6y = 18 128+22y=18128 + 22y = 18

Step 7: Solve for yy

Subtract 128 from both sides:

22y=1812822y = 18 - 128 22y=11022y = -110

Now, divide by 22:

y=11022=5y = \frac{-110}{22} = -5

Step 8: Conclusion

The point on the y-axis that is equidistant from (8,8)(8, -8) and (3,3)(3, 3) is (0,5)(0, -5).


Would you like further details on this solution? Here are five related questions to explore:

  1. How can you use the midpoint formula to check if the point (0,5)(0, -5) lies on the perpendicular bisector of the two given points?
  2. What is the significance of symmetry when finding points equidistant from two given points?
  3. How would the problem change if the point was restricted to the x-axis instead of the y-axis?
  4. Can you find the equation of the circle that passes through the points (8,8)(8, -8) and (3,3)(3, 3) with center (0,5)(0, -5)?
  5. How does this method generalize for finding points equidistant from two points in three-dimensional space?

Tip: When solving distance problems, always use the symmetry of the coordinate axes to simplify the computation process.

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Math Problem Analysis

Mathematical Concepts

Geometry
Distance Formula
Coordinate Geometry
Algebra

Formulas

Distance formula: d = sqrt((x2 - x1)^2 + (y2 - y1)^2)

Theorems

Equidistance theorem: A point is equidistant from two other points if its distances to both points are equal.

Suitable Grade Level

Grades 9-11