y = $\sqrt{x+\sqrt{x+\sqrt{x+......}}}$ হলে $\frac{dy}{dx} = কত?$ Barisal • 2023 ক (ক) $\frac{1}{2y}$ খ (খ) $\frac{1}{-2y}$ গ (গ) $\frac{1}{2y-1}$ ঘ (ঘ) $\frac{1}{1-2y}$