Math Problem Statement

The roots of quadratic equation ax2 + bx + c = 0 are p and q. What will be the quadratic equation whose roots are 1/p^2and1/q^2?

Solution

To find the quadratic equation with roots 1p2\frac{1}{p^2} and 1q2\frac{1}{q^2}, let's proceed with the following steps:

Step 1: Sum and Product of Original Roots

For the original quadratic equation ax2+bx+c=0ax^2 + bx + c = 0, with roots pp and qq, we know:

  1. Sum of the roots p+q=bap + q = -\frac{b}{a}
  2. Product of the roots pq=capq = \frac{c}{a}

Step 2: Determine the Sum and Product of New Roots

The new roots are 1p2\frac{1}{p^2} and 1q2\frac{1}{q^2}.

  1. Sum of new roots: 1p2+1q2=p2+q2p2q2\frac{1}{p^2} + \frac{1}{q^2} = \frac{p^2 + q^2}{p^2 q^2} Using the identity p2+q2=(p+q)22pqp^2 + q^2 = (p + q)^2 - 2pq, we get: p2+q2=(ba)22ca=b22aca2p^2 + q^2 = \left(-\frac{b}{a}\right)^2 - 2 \cdot \frac{c}{a} = \frac{b^2 - 2ac}{a^2} Therefore, 1p2+1q2=b22aca2(ca)2=b22acc2\frac{1}{p^2} + \frac{1}{q^2} = \frac{\frac{b^2 - 2ac}{a^2}}{\left(\frac{c}{a}\right)^2} = \frac{b^2 - 2ac}{c^2}

  2. Product of new roots: 1p21q2=1(pq)2=1(ca)2=a2c2\frac{1}{p^2} \cdot \frac{1}{q^2} = \frac{1}{(pq)^2} = \frac{1}{\left(\frac{c}{a}\right)^2} = \frac{a^2}{c^2}

Step 3: Form the New Quadratic Equation

A quadratic equation with roots α\alpha and β\beta can be written as: x2(sum of roots)x+(product of roots)=0x^2 - (\text{sum of roots}) \cdot x + (\text{product of roots}) = 0

Substituting the values for our new roots: x2(b22acc2)x+a2c2=0x^2 - \left(\frac{b^2 - 2ac}{c^2}\right)x + \frac{a^2}{c^2} = 0

Final Answer

The required quadratic equation whose roots are 1p2\frac{1}{p^2} and 1q2\frac{1}{q^2} is: c2x2(b22ac)x+a2=0c^2 x^2 - (b^2 - 2ac)x + a^2 = 0

Would you like further clarification on any step?


  1. How do we find the roots of a transformed quadratic equation?
  2. Why is the product of roots important in forming a new quadratic equation?
  3. How can we verify roots without solving the entire equation?
  4. What are other ways to manipulate polynomial roots for transformation?
  5. How does changing roots impact the coefficients of the new polynomial?

Tip: When transforming a quadratic equation, always check the sum and product of the new roots for consistency.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Roots of Quadratic Equations
Sum and Product of Roots

Formulas

Sum of roots: p + q = -b/a
Product of roots: pq = c/a
p^2 + q^2 = (p + q)^2 - 2pq
Quadratic equation form: x^2 - (sum of roots) * x + (product of roots) = 0

Theorems

Vieta's Formulas
Sum and Product of Roots of Quadratic Equations

Suitable Grade Level

Grades 9-11