Math Problem Statement

A curve has equation y = 2xy+5 and a line has equation 2x +5y= 1.

The curve and the line intersect at the points A and B. Find the coordinates of the midpoint

of the line AB.

Solution

To find the coordinates of the midpoint of the line segment ABAB where the curve y=2xy+5y = 2xy + 5 and the line 2x+5y=12x + 5y = 1 intersect, we need to solve for the points of intersection and then calculate the midpoint. Here are the steps:

  1. Solve the system of equations:
    y=2xy+5(Equation 1)y = 2xy + 5 \quad \text{(Equation 1)} 2x+5y=1(Equation 2)2x + 5y = 1 \quad \text{(Equation 2)}

  2. Substitute Equation 1 into Equation 2 to express yy in terms of xx.

Step 1: Rearrange and Substitute

From Equation 1: y=2xy+5y = 2xy + 5 This can be rearranged to: y2xy=5y(12x)=5y=512xy - 2xy = 5 \quad \Rightarrow \quad y(1 - 2x) = 5 \quad \Rightarrow \quad y = \frac{5}{1 - 2x}

Substitute this expression for yy in Equation 2: 2x+5(512x)=12x + 5\left(\frac{5}{1 - 2x}\right) = 1

Step 2: Solve for xx

Simplify and solve the equation: 2x+2512x=12x + \frac{25}{1 - 2x} = 1

Multiply through by 12x1 - 2x to clear the fraction: 2x(12x)+25=12x2x(1 - 2x) + 25 = 1 - 2x

Expanding: 2x4x2+25=12x2x - 4x^2 + 25 = 1 - 2x

Rearrange terms: 4x2+4x+24=0-4x^2 + 4x + 24 = 0

Divide through by 4-4: x2x6=0x^2 - x - 6 = 0

Step 3: Solve the Quadratic Equation

Factor the quadratic equation: x2x6=(x3)(x+2)=0x^2 - x - 6 = (x - 3)(x + 2) = 0

The solutions are: x=3orx=2x = 3 \quad \text{or} \quad x = -2

Step 4: Find Corresponding yy Values

For x=3x = 3: y=512(3)=516=55=1y = \frac{5}{1 - 2(3)} = \frac{5}{1 - 6} = \frac{5}{-5} = -1

For x=2x = -2: y=512(2)=51+4=55=1y = \frac{5}{1 - 2(-2)} = \frac{5}{1 + 4} = \frac{5}{5} = 1

Step 5: Find the Midpoint of ABAB

The points of intersection are A(3,1)A(3, -1) and B(2,1)B(-2, 1).

The midpoint MM of the line segment ABAB is calculated as: M=(x1+x22,y1+y22)M = \left(\frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2}\right)

Substituting the values: M=(3+(2)2,1+12)=(12,0)M = \left(\frac{3 + (-2)}{2}, \frac{-1 + 1}{2}\right) = \left(\frac{1}{2}, 0\right)

Thus, the coordinates of the midpoint are (12,0)\left(\frac{1}{2}, 0\right).

Would you like further details or have any questions about this solution? Here are some related questions that might help deepen your understanding:

  1. How do you derive the equation of a line from two points?
  2. What are other methods to solve quadratic equations?
  3. How can you find the point of intersection for two non-linear equations?
  4. What are the properties of a quadratic curve?
  5. How can a graphical method help in visualizing the solutions?
  6. How does changing the coefficients of the equations affect their points of intersection?
  7. What happens when a curve and line do not intersect?
  8. How do transformations affect the geometry of a line or a curve?

Tip: When solving simultaneous equations involving non-linear terms, substituting one equation into the other to eliminate a variable can often simplify the problem significantly.

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Math Problem Analysis

Mathematical Concepts

Intersection of Curves and Lines
Midpoint Formula
Quadratic Equations

Formulas

Midpoint formula

Theorems

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Suitable Grade Level

Grades 10-12