MathematicsSolution of Quadratic EquationsJEE Advanced 1986Moderate
Visualized Solution (Hindi)
Identifying the Pivot Point x=a
- Given equation: x2−2a∣x−a∣−3a2=0 with a≤0.
- The critical point for the modulus ∣x−a∣ is x=a.
- We must analyze the equation in two domains: x≥a and x<a.
Case 1: x≥a
- For x≥a, ∣x−a∣=x−a.
- Substitute into the equation: x2−2a(x−a)−3a2=0.
- Expand the terms: x2−2ax+2a2−3a2=0.
Solving Case 1: x2−2ax−a2=0
- Simplified Quadratic: x2−2ax−a2=0.
- Using Quadratic Formula: x=2(1)−(−2a)±(−2a)2−4(1)(−a2).
- Calculation: x=22a±4a2+4a2=22a±2a2.
- Roots for Case 1: x=a±a2.
Case 2: x<a
- For x<a, ∣x−a∣=−(x−a)=a−x.
- Substitute into the equation: x2−2a(a−x)−3a2=0.
- Expand the terms: x2−2a2+2ax−3a2=0.
Solving Case 2: x2+2ax−5a2=0
- Simplified Quadratic: x2+2ax−5a2=0.
- Using Quadratic Formula: x=2(1)−(2a)±(2a)2−4(1)(−5a2).
- Calculation: x=2−2a±4a2+20a2=2−2a±2a6.
- Roots for Case 2: x=−a±a6.
Summary of Real Roots
- The complete set of real roots is obtained by combining both cases.
- Final Roots: {a±a2,−a±a6}.
- Key Takeaway: Always split absolute value equations at their critical points to simplify the problem into standard algebraic forms.
00:00 / 00:00
Conceptually Similar Problems
MathematicsLocation of RootsJEE Advanced 1999Moderate
MathematicsRelation Between Roots and CoefficientsJEE Advanced 2001Easy
MathematicsLogarithmic Equations and InequalitiesJEE Advanced 1978Easy
MathematicsSolution of Quadratic EquationsJEE Advanced 1982Easy
MathematicsLocation of RootsJEE Advanced 1989Moderate
MathematicsSolution of Quadratic EquationsJEE Advanced 1983Easy
MathematicsLocation of RootsJEE Advanced 1995Easy
MathematicsNature of RootsJEE Advanced 2003Easy
MathematicsEvaluation of Limits & L'Hopital's RuleJEE Advanced 1978Easy
MathematicsRelation Between Roots and CoefficientsJEE Main 2003Easy