0606/21 May/Jun 2025, Question 2: The Discriminant and Nature of Roots
Cambridge IGCSE Additional Mathematics 0606 · Paper 21 (Calculator) · Calculator · 5 marks
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The question, in short
Given the quadratic 2x² + (3k − 2)x + k = 0 with real distinct roots, find the set of possible values of the constant k.
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Solution · 5 marks
- 1Real distinct roots: b² − 4ac > 0
- 2(3k − 2)² − 4(2)(k) > 0
- 39k² − 20k + 4 > 0
- 4(9k − 2)(k − 2) > 0, critical values 2/9 and 2
- 5k < 2/9 or k > 2
Answerk < 2/9, k > 2
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Also searched as: 0606/21/M/J/25 · 0606_s25_qp_21 · 0606 s25 21 · question 2.
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