Quadratic Equations and Theory of Equations

Nature of Roots and Advanced Conditions

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Nature of Roots and Advanced Conditions

Nature of Roots and Advanced Conditions

This lesson covers the following key concepts:

  • Nature of roots based on discriminant
  • Real and distinct roots (D > 0)
  • Real and equal roots (D = 0)
  • Complex conjugate roots (D < 0)
  • Rational roots condition (D = perfect square)
  • Conditions for both roots positive, negative, opposite signs
  • Relation between coefficients for specific root conditions

Important Formulas

  • D>0:real and distinct rootsD > 0: \text{real and distinct roots}
  • D=0:real and equal rootsD = 0: \text{real and equal roots}
  • D<0:complex conjugate rootsD < 0: \text{complex conjugate roots}
  • D>0,D=k2:rational rootsD > 0, D = k^2: \text{rational roots}
  • Both roots positive: α+β>0,αβ>0,D0\text{Both roots positive: } \alpha + \beta > 0, \alpha\beta > 0, D \geq 0
  • Both roots negative: α+β<0,αβ>0,D0\text{Both roots negative: } \alpha + \beta < 0, \alpha\beta > 0, D \geq 0
  • Opposite signs: αβ<0\text{Opposite signs: } \alpha\beta < 0