Question

Let a, b and c be the sides of a triangle and a² + b² + c²/ab + bc + ca = P. Then

(A)  1 ≤ P ≤ 2 

(B)  1 < P ≤ 2 

(C)  1 < P < 2 

(D)  1 ≤ P < 2

Answer 1

Correct option (D) 1 ≤ P < 2

(a² + b² + c²)/(ab + bc + ca) = p

From Eqs. (1) and (5), we get 1 ≤ p < 2.