NTA Abhyas JEE Main2020MathematicsSequences and SeriesPractice
If a + b + c = 3 where a , b , c > 0 , then the greatest value of a 2 b 3 c 2 is
Options
- A3 10 2 4 7 7
- B3 9 2 4 7 7
- C3 8 2 4 7 7
- D3 9 2 3 7 6
Correct answer
A. 3 10 2 4 7 7
Step-by-step solution
Given, a + b + c = 3 ⇒ 2 ⋅ a 2 + 3 ⋅ b 3 + 2 ⋅ c 2 = 3 a 2 + a 2 + b 3 + b 3 + b 3 + c 2 + c 2 7 ≥ a 2 2 b 3 3 c 2 2 1 7 a + b + c 7 ≥ a 2 b 3 c 2 2 4 3 3 1 7 3 7 7 ≥ a 2 b 3 c 2 2 4 3 3 ⇒ a 2 b 3 c 2 ≤ 3 7 7 7 × 2 4 × 3 3 = 2 4 × 3 10 7 7 Hence, maximum value = 2 4 × 3 10 7 7