(i) If \(y = \sinh^{-1}x\), prove that for \(n>2\) \[ (1+x^2)\frac{d^ny}{dx^n} + x(2n-3)\frac{d^{n-1}y}{dx^{n-1}} + (n-2)^2 \frac{d^{n-2}y}{dx^{n-2}} = 0. \] (ii) Find the most general form of \(y\) which will satisfy the condition \[ y \frac{d^2y}{dx^2} = \left(\frac{dy}{dx}\right)^2. \]