What is the nature of the roots of the equation \(x^2-4x+1=0\)?
Answer and explanation
Correct answer: Two real, irrational and distinct roots (\(D=12\))
For a quadratic equation \(ax^2+bx+c=0\), the discriminant is \(D=b^2-4ac\). Here, \(a=1, b=-4, c=1\), so \(D=(-4)^2-4(1)(1)=12\). Since \(D>0\) and 12 is not a perfect square, the roots are real, irrational, and distinct. Option B is incorrect because \(D=16\) is not the discriminant of this equation. Exam tip: First use the sign of \(D\) to determine whether the roots are real and distinct, then check whether \(D\) is a perfect square to determine rationality.
Frequently asked questions
What is the correct answer to this question?
Two real, irrational and distinct roots (\(D=12\))
Why is this the correct answer?
For a quadratic equation \(ax^2+bx+c=0\), the discriminant is \(D=b^2-4ac\). Here, \(a=1, b=-4, c=1\), so \(D=(-4)^2-4(1)(1)=12\). Since \(D>0\) and 12 is not a perfect square, the roots are real, irrational, and distinct. Option B is incorrect because \(D=16\) is not the discriminant of this equation. Exam tip: First use the sign of \(D\) to determine whether the roots are real and distinct, then check whether \(D\) is a perfect square to determine rationality.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Quadratic Equations. Topic: Nature of Roots.
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