1.

If x = a secθ, y = b tanθ, then d2y/dx2 at θ = π/6 is :(a) \(\frac{-3\sqrt 3b}{a^2}\)(b) \(\frac{-2\sqrt 3b}{a}\)(c) \(\frac{-3\sqrt 3b}{a}\)(d) \(\frac{-b}{3\sqrt 3a^2}\)

Answer»

Option : (a)

x = a secθ

⇒ \(\frac{dx}{d\theta}\) = a tanθ secθ

y = b tanθ

⇒ \(\frac{dy}{d\theta}\) = b sec2θ

∴ \(\frac{dy}{dx}\) = \(\frac{b}{a}\) cosecθ

⇒ \(\frac{d^2y}{dx^2}\) = \(\frac{-b}{a}\)cosecθ.cotθ.\(\frac{d\theta}{dx}\)

\(\frac{-b}{a^2}\) cot3θ

∴ \(\frac{d^2y}{dx^2}\)]θ = \(\frac{\pi}{6}\) \(\frac{-3\sqrt 3b}{a^2}\)



Discussion

No Comment Found

Related InterviewSolutions