Practicing Success
The normal to the curve $x=a(1+\cos \theta)$, $y=a \sin \theta$ at '$\theta$' always passes through the fixed point |
(a, a) (a, 0) (0, a) none of these |
(a, 0) |
We have, $x=a(1+\cos \theta), y=a \sin \theta$ ∴ $\frac{d y}{d x}=\frac{\frac{d y}{d \theta}}{\frac{d x}{d \theta}}=\frac{a \cos \theta}{-a \sin \theta}=-\cot \theta$ The equation of the normal at $(a(1+\cos \theta), a \sin \theta)$ is $y-a \sin \theta=\tan \theta\{x-a(1+\cos \theta)\}$ $\Rightarrow x \sin \theta-y \cos \theta=a \sin \theta$ Clearly, it passes through (a, 0). |