Differentiation Question 433

Question: If $ y={e^{x+{e^{x+{e^{x+….\infty }}}}}} $ , then $ \frac{dy}{dx}= $

[AISSE 1990; UPSEAT 2002; DCE 2002]

Options:

A) $ \frac{y}{1-y} $

B) $ \frac{1}{1-y} $

C) $ \frac{y}{1+y} $

D) $ \frac{y}{y-1} $

Show Answer

Answer:

Correct Answer: A

Solution:

$ y={e^{x+y}} $

Therefore $ \log y=(x+y)\log e $

Therefore $ \frac{1}{y}\frac{dy}{dx}=1+\frac{dy}{dx} $

Therefore $ ={{\sin }^{2}}\alpha +\frac{1}{2}(\cos 2\alpha +\cos 2\beta ) $ .