NDA2017MathematicsSequences and SeriesActual
If x₁ and x₂ are positive quantities, then the condition for the difference between the arithmetic mean and the geometric mean to be greater than 1 is
Options
- Ax ₁+ x ₂ 2 x ₁ x ₂
- Bx ₁ + x ₂ 2
- C| x ₁ - x ₂ | 2
- Dx ₁+ x ₂ 2 ( x ₁ x ₂ +1 )
Correct answer
C. | x ₁ - x ₂ | 2
Step-by-step solution
Arithmetic mean of x₁, x₂= x₁+x₂ 2 Geometric mean of x ₁, x ₂= x ₁ x ₂ Given, x ₁+ x ₂ 2 - x ₁ x ₂ 1 x ₁+ x ₂ 2 x ₁ x ₂ +1 aligned & x ₁+ x ₂ 2 x ₁ x ₂ +2 & x ₁+ x ₂-2 x ₁ x ₂ 2 & ( x ₁ )^2+ ( x ₂ )^2-2 x ₁ x ₂ 2 aligned aligned & ( x ₁ - x ₂ )^2 2 & | x ₁ - x ₂ | 2 aligned