Min of sumHardQuestion 210034
Question
If a, b are positive with a+b = 1, the minimum of (a + 1/a)² + (b + 1/b)² is:
- A25/2Correct
- B12.5
- C50
- D25
Correct answer
25/2
Explanation
By AM inequality and symmetry: minimum occurs at a = b = 1/2. Each bracket = (1/2 + 2)² = (5/2)² = 25/4. Sum = 25/4 + 25/4 = 25/2.