Question

1] sec²theta = 4ab/(a+b)² is always true when

(A) a<b
(B) a>b
(C) a=b
(D) None of these

Answer 1

Answer:

Option(C)

Step-by-step explanation:

We know that sec² θ ≥ 1

= (4ab)/(a+b)² ≥ 1

= 4ab ≥ (a + b)²

= 4ab ≥ a² + b² + 2ab

= a² + b² - 2ab ≤ 0

= (a - b)² ≤ 0

= (a - b) = 0

∴ a = b.

Therefore, Sec²θ = 4ab/(a + b)² is always true when a = b.

Hope it helps!