Practicing Success
If cot2 θ = 3 - a2, then cosec θ + cot3 θ. sec θ =? |
(4 - a2)\(\frac{3}{2}\) (4 + a2)\(\frac{3}{2}\) (4 + a2)\(\frac{5}{2}\) (4 - a2)\(\frac{5}{2}\) |
(4 - a2)\(\frac{3}{2}\) |
Let put θ = 45° ⇒ cot2 θ = 3 - a2 ⇒ 1 = 3 - a2 ⇒ a2 = 2 and ⇒ cosec θ + cot3θ . sec θ = cosec 45° + cot3 45° × sec 45° = \(\sqrt {2}\) + \(\sqrt {2}\) = 2\(\sqrt {2}\) Now put a2 = 2 in options and find answer (4 - a2)\(\frac{3}{2}\) = (2)\(\frac{3}{2}\) = 2\(\sqrt {2}\) Hence, option (1) is correct answer. |