Math Problem Statement

The graph of the function f(x) = px? - x + 3 does not touch or cross the x-axis. What are the possible values for p?

Solution

The function f(x)=px2x+3f(x) = px^2 - x + 3 is a quadratic equation, and we are told that its graph does not touch or cross the x-axis. This means that the quadratic has no real solutions, and thus its discriminant must be negative.

For a quadratic equation of the form ax2+bx+c=0ax^2 + bx + c = 0, the discriminant is given by:

Δ=b24ac\Delta = b^2 - 4ac

In this case:

  • a=pa = p,
  • b=1b = -1,
  • c=3c = 3.

Substitute these values into the discriminant formula:

Δ=(1)24(p)(3)=112p\Delta = (-1)^2 - 4(p)(3) = 1 - 12p

For the quadratic to have no real solutions, we need Δ<0\Delta < 0:

112p<01 - 12p < 0

Solve this inequality:

1<12p1 < 12p

p>112p > \frac{1}{12}

Thus, the function f(x)=px2x+3f(x) = px^2 - x + 3 does not touch or cross the x-axis when p>112p > \frac{1}{12}.

Would you like more details or have any questions?

Here are 5 related questions you might want to explore:

  1. What happens to the function when p=112p = \frac{1}{12}?
  2. How do we find the vertex of a quadratic function?
  3. What is the significance of the discriminant in quadratic equations?
  4. How does changing the value of pp affect the shape of the parabola?
  5. What are the x-intercepts of a quadratic equation?

Tip: The discriminant is a useful tool for quickly determining the nature of the roots of any quadratic equation.

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Math Problem Analysis

Mathematical Concepts

Quadratic Equations
Discriminant
Inequalities

Formulas

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

Theorems

Discriminant Theorem for quadratic equations

Suitable Grade Level

Grades 9-12