If $y=x\sin y$, then $\frac{dy}{dx}$ is: |
$\frac{\sin y}{x-\cos y}$ $\frac{\sin^2 y}{\sin y-y \cos y}$ $\frac{\sin^2 y}{\cos y-y \sin y}$ $\frac{\sin y}{x\cos y+y}$ |
$\frac{\sin^2 y}{\sin y-y \cos y}$ |
The correct answer is Option (2) → $\frac{\sin^2 y}{\sin y-y \cos y}$ $y = x \sin y$ Differentiate both sides: $\frac{dy}{dx} = \sin y + x \cos y \cdot \frac{dy}{dx}$ Bring $\frac{dy}{dx}$ terms together: $\frac{dy}{dx} - x \cos y \frac{dy}{dx} = \sin y$ $\frac{dy}{dx}(1 - x \cos y) = \sin y$ Since $x = \frac{y}{\sin y}$ from the original equation: $1 - x \cos y = 1 - \frac{y \cos y}{\sin y} = \frac{\sin y - y \cos y}{\sin y}$ Hence: $\frac{dy}{dx} = \frac{\sin y}{\frac{\sin y - y \cos y}{\sin y}} = \frac{\sin^2 y}{\sin y - y \cos y}$ $\frac{dy}{dx} = \frac{\sin^2 y}{\,\sin y - y \cos y\,}$ |