1.

Find second derivative of ex = tan2y with respect to x.

Answer»

ex = tan 2y----(1)

differentiate (1) w.r.t. x we get

ex = 2 sec22y.\(\frac{dy}{dx}\)----(2)

differentiate (2) w.r.t. x, we get

ex = 2sec22y \(\frac{d^2y}{dx^2}+\) 8sec 2y. sec 2y tan 2y \((\frac{dy}{dx})^2\) 

 = 2 sec22y.\(\frac{d^2y}{dx^2}+\) 8 sec22y tan 2y \((\frac{e^x}{2sec^22y})^2\) (From (2))

 = 2 sec22y \(\frac{d^2y}{dx^2}+\) 2 \(\frac{tan2y}{sec^22y}e^{2x}\)

⇒ 2 sec22y.\(\frac{d^2y}{dx^2}\) = ex - \(\frac{2tan2y}{sec^22y}e^{2x}\)

⇒ 2(1 + tan22y)\(\frac{d^2y}{dx^2}\) = ex - \(\frac{2.e^x.e^{2x}}{1+tan^22y}\) (\(\because\) 1 + tan2\(\theta\) = sec2\(\theta\) and From (1))

⇒ 2(1 + e2x\(\frac{d^2y}{dx^2}\) = ex - \(\frac{2e^{3x}}{1+e^{2x}}\)

⇒ \(\frac{d^2y}{dx^2}\) = \(\frac{e^{3x}+e^x-2e^{3x}}{2(1+e^{2x})^2}\)



Discussion

No Comment Found

Related InterviewSolutions