\(I=tan^{-1}\sqrt{\frac{1-x}{1+x}}\)
\(Let\space x=cosθ⇒dx=-sinθdθ\)
\(I=\int tan^{-1}\sqrt{\frac{1-cosθ}{1+cosθ}}(-sinθdθ)\)
\(=-\int tan^{-1}\sqrt{\frac{2sin^{2}\frac{θ}{2}}{2cos^{2}\frac{θ}{2}}}sinθdθ\)
\(=-\int tan^{-1}tan\frac{θ}{2}.sinθdθ\)
\(=-\frac{1}{2}∫θ.sinθdθ\)
\(=-\frac{1}{2}[θ.(-cosθ)-∫1.(-cosθ)dθ]\)
\(=-\frac{1}{2}[-θcosθ+sinθ]\)
\(=+\frac{1}{2}θcosθ-\frac{1}{2}sinθ\)
\(=\frac{1}{2}cos^{-1}x.x-\frac{1}{2}\sqrt{1-x^{2}}+C\)
\(=\frac{x}{2}cos^{-1}x-\frac{1}{2}\sqrt{1-x^{2}}+C\)
\(=\frac{1}{2}(xcos^{-1}x-\sqrt{1-x^{2}})+C\)
Let \( f : (0, \infty) \to \mathbb{R} \) be a twice differentiable function. If for some \( a \neq 0 \), } \[ \int_0^a f(x) \, dx = f(a), \quad f(1) = 1, \quad f(16) = \frac{1}{8}, \quad \text{then } 16 - f^{-1}\left( \frac{1}{16} \right) \text{ is equal to:}\]

A ladder of fixed length \( h \) is to be placed along the wall such that it is free to move along the height of the wall.
Based upon the above information, answer the following questions:
(iii) (b) If the foot of the ladder, whose length is 5 m, is being pulled towards the wall such that the rate of decrease of distance \( y \) is \( 2 \, \text{m/s} \), then at what rate is the height on the wall \( x \) increasing when the foot of the ladder is 3 m away from the wall?