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AP EAMCET · Maths · Quadratic Equation

The difference of the irrational roots of the equation \(x^5-5 x^4+9 x^3-9 x^2+5 x-1=0\) is

  1. A \(\sqrt{3}\)
  2. B \(2 \sqrt{5}\)
  3. C \(3\)
  4. D \(\sqrt{5}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(\sqrt{5}\)

Step-by-step Solution

Detailed explanation

\(P(x) = x^5-5 x^4+9 x^3-9 x^2+5 x-1\) \(P(1) = 1-5+9-9+5-1 = 0\). Thus, \(x=1\) is a root. \((x^5-5 x^4+9 x^3-9 x^2+5 x-1) \div (x-1) = x^4-4x^3+5x^2-4x+1 = 0\) Divide by \(x^2\): \(x^2-4x+5-4/x+1/x^2 = 0\) \((x^2+1/x^2) - 4(x+1/x) + 5 = 0\) Let \(y=x+1/x\), then…