KVPY2012MathematicsFunctions
Let f: R R be the function f(x)= (x-a₁ ) (x-a₂ )+ (x-a₂ ) (x-a₃ )+ (x-a₃ ) (x-a₁ ) with a₁, a₂, a₃ R . Then f(x) 0 if and only if -
Options
- AAt least two of a_ i , a₇, a₇ are equal
- Ba_ i =a_ i =a₇
- Ca ₁, a ₂, a ₃ are all distinct
- Da ₁, a ₂, a ₃ , are all positive and distinct
Correct answer
B. a_ i =a_ i =a₇
Step-by-step solution
Only when a ₁= a ₂= a ₃ In other cases f ( x ) will take both positive and negative values