# Question #b5ac6

Apr 2, 2017

Normal would be vertical line parallel to y axis, hence its slope would be undefined.

#### Explanation:

$\frac{\mathrm{dx}}{\mathrm{dt}} = - a \sin t$ and $\frac{\mathrm{dy}}{\mathrm{dt}} = a \cos t$

this gives $\frac{\mathrm{dy}}{\mathrm{dx}} = - \cos \frac{t}{\sin} t$

At t= ${90}^{o} = \frac{\pi}{2}$, $\frac{\mathrm{dy}}{\mathrm{dx}} = - \frac{0}{1} = 0$

The slope at t= pi/2 is thus 0, that means the tangent is a horizontal line that is parallel to x axis.

The normal to this horizontal tangent would thus be a vertical line. Its slope would therefor be undefined,