Prove that the curves $y^{2}=4 x$ and
$x^{2}+y^{2}-6 x+1=0$ touch each other at the point $(1,2)$
Given:
Curves $y^{2}=4 x \ldots(1)$
$\& x^{2}+y^{2}-6 x+1=0$ ......(2)
$\therefore$ The point of intersection of two curves is $(1,2)$
First curve is $y^{2}=4 x$
Differentiating above w.r.t $\mathrm{x}$,
$\Rightarrow 2 y \cdot \frac{d y}{d x}=4$
$\Rightarrow y \cdot \frac{d y}{d x}=2$
$\Rightarrow m_{1}=\frac{2}{y} \ldots(3)$
Second curve is $x^{2}+y^{2}-6 x+1=0$
$\Rightarrow 2 x+2 y \cdot \frac{d y}{d x}-6-0=0$
$\Rightarrow x+y \cdot \frac{d y}{d x}-3=0$
$\Rightarrow y \cdot \frac{d y}{d x}=3-x$
$\Rightarrow \frac{d y}{d x}=\frac{3-x}{y} \ldots(4)$
At $(1,2)$, we have,
$m_{1}=\frac{2}{y}$
At $(1,2)$, we have,
$\Rightarrow m_{2}=\frac{3-x}{y}$
$\Rightarrow \frac{3-1}{2}$
$\Rightarrow m_{2}=1$
Clearly, $m_{1}=m_{2}=1$ at $(1,2)$
So, given curve touch each other at $(1,2)$