Math Problem Statement

it is geven that the curve y = (p-1)x^2 - x + 5 where p is a constant, interesects with the straight line y = 2x + 3 at two points. Find the range of values of p.

Solution

To find the range of values of pp for which the curve y=(p1)x2x+5y = (p-1)x^2 - x + 5 intersects the straight line y=2x+3y = 2x + 3 at two points, we need to set the two equations equal to each other and solve for xx.

The two equations are:

  1. y=(p1)x2x+5y = (p-1)x^2 - x + 5
  2. y=2x+3y = 2x + 3

Step 1: Set the equations equal

(p1)x2x+5=2x+3(p-1)x^2 - x + 5 = 2x + 3

Step 2: Rearrange the equation

Move all terms to one side: (p1)x2x+52x3=0(p-1)x^2 - x + 5 - 2x - 3 = 0 Simplify: (p1)x23x+2=0(p-1)x^2 - 3x + 2 = 0

Step 3: Determine the discriminant for real intersections

For the quadratic equation (p1)x23x+2=0(p-1)x^2 - 3x + 2 = 0 to have two real solutions (indicating two points of intersection), the discriminant must be positive. The discriminant Δ\Delta of a quadratic equation ax2+bx+c=0ax^2 + bx + c = 0 is given by: Δ=b24ac\Delta = b^2 - 4ac For our equation (p1)x23x+2=0(p-1)x^2 - 3x + 2 = 0, we have:

  • a=p1a = p-1
  • b=3b = -3
  • c=2c = 2

The discriminant is: Δ=(3)24(p1)(2)\Delta = (-3)^2 - 4(p-1)(2) Δ=98(p1)\Delta = 9 - 8(p-1) Δ=98p+8\Delta = 9 - 8p + 8 Δ=178p\Delta = 17 - 8p

Step 4: Solve for the condition for two intersections

For two real intersections, we need the discriminant to be positive: 178p>017 - 8p > 0

Solving for pp: 17>8p17 > 8p p<178p < \frac{17}{8} Thus, the value of pp must satisfy: p<178=2.125p < \frac{17}{8} = 2.125

Step 5: Conclusion

The curve y=(p1)x2x+5y = (p-1)x^2 - x + 5 intersects the line y=2x+3y = 2x + 3 at two points if: p<2.125p < 2.125

Final Answer:

The range of values of pp for which the curve intersects the line at two points is p<2.125p < 2.125.


Would you like further clarification or a detailed explanation of any part? Here are 5 follow-up questions:

  1. How would the solution change if we required only one point of intersection?
  2. Can you derive the points of intersection for a specific value of pp?
  3. What happens to the curve when pp is greater than 2.125?
  4. How does the discriminant help us determine the nature of the solutions to a quadratic equation?
  5. How would the equation change if the line had a different slope or y-intercept?

Tip: Always remember that the discriminant of a quadratic equation gives you the number and type of solutions. A positive discriminant means two real solutions, zero means one real solution, and a negative discriminant means no real solutions.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Discriminant

Formulas

Discriminant formula: Δ = b^2 - 4ac
Quadratic equation: ax^2 + bx + c = 0

Theorems

Discriminant Theorem

Suitable Grade Level

Grades 9-11