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What is the maximum value of expression x2/(2x + 3)? |
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Answer» Correct Answer - Option 3 : Cannot be determined GIVEN: Expression = x2/(2x + 3) CONCEPT: Maximum value of the expression CALCULATION: Let k = x2/(2x + 3) ⇒ k (2x + 3) = x2 ⇒ 2kx + 3k = x2 ⇒ x2 – 2kx – 3k = 0 For all real value of ‘x’, D ≥ 0 D = b2 – 4ac ≥ = 0 After comparing above equation with ax2 + bx + c = 0 a = 1, b = -2k and c = -3k ⇒ (-2k)2 – 4 × 1 × (-3k) ≥ 0 ⇒ 4k2 + 12k ≥ 0 ⇒ 4k (k + 3) ≥ 0 ⇒ k ≥ 0 and k ≤ -3 ⇒ k = (-∞, -3] ∪ [0, ∞) Hence, maximum value of the expression cannot be determined. |
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