Question:
Find the equation of the tangent and the normal to the following curves at the indicated points:
$y^{2}=4 x$ at $(1,2)$
Solution:
Find the equation of the tangent and the normal to the following curves at the indicated points:
$2 y \frac{d y}{d x}=4$
$\frac{\mathrm{dy}}{\mathrm{dx}}=\frac{2}{\mathrm{y}}$
$\mathrm{m}$ (tangent) at $(1,2)=1$
normal is perpendicular to tangent so, $m_{1} m_{2}=-1$
equation of tangent is given by $y-y_{1}=m($ tangent $)\left(x-x_{1}\right)$
$y-2=1(x-1)$
equation of normal is given by $y-y_{1}=m($ normal $)\left(x-x_{1}\right)$
$y-2=-1(x-1)$