Solve the quadratic equation:
\[ m = \frac{10 \pm \sqrt{100 - 36}}{18} = \frac{10 \pm 8}{18} \]
So \(m_1 = 1\) and \(m_2 = \frac{1}{9}\)
The two tangent equations are:
\[ y = x - 3 \]
\[ y = \frac{1}{9}x + \frac{13}{9} \]
or in standard form:
\[ x - y - 3 = 0 \]
\[ x - 9y + 13 = 0 \]
2 Hyperbola Tangents Parallel to Line
Find the equations of tangents to the hyperbola \(\frac{x^2}{16} - \frac{y^2}{64} = 1\) which are parallel to \(10x - 3y + 9 = 0\).
First, find the slope of the given line \(10x - 3y + 9 = 0\):
\[ 3y = 10x + 9 \Rightarrow y = \frac{10}{3}x + 3 \]
So slope \(m = \frac{10}{3}\)
The condition for tangency to the hyperbola \(\frac{x^2}{a^2} - \frac{y^2}{b^2} = 1\) is:
\[ c^2 = a^2m^2 - b^2 \]
Here \(a^2 = 16\), \(b^2 = 64\), and \(m = \frac{10}{3}\)
The normal equation is:
\[ \frac{ax}{\sec\theta} + \frac{by}{\tan\theta} = a^2 + b^2 \]
\[ \frac{3x}{2} + \frac{2\sqrt{3}y}{\sqrt{3}} = 9 + 12 \]
The tangent equation is:
\[ 4x - 3y - 6 = 0 \]
The normal equation is:
\[ 3x + 4y - 42 = 0 \]
7 Intersection of Parabola Tangents
Prove that the point of intersection of the tangents at '\( t_1 \)' and '\( t_2 \)' on the parabola \( y^2 = 4ax \) is \[ [at_1t_2, a(t_1 + t_2)] \].
The tangent at \( t_1 \) is:
\[ yt_1 = x + at_1^2 \]
The tangent at \( t_2 \) is:
\[ yt_2 = x + at_2^2 \]
Subtract the two equations:
\[ y(t_1 - t_2) = a(t_1^2 - t_2^2) \]
\[ y = a(t_1 + t_2) \]
Substitute back to find x:
\[ x = yt_1 - at_1^2 = at_1(t_1 + t_2) - at_1^2 = at_1t_2 \]
The point of intersection is:
\[ \boxed{(at_1t_2, a(t_1 + t_2))} \]
8 Parabola Normal Property
If the normal at the point '\( t_1 \)' on the parabola \( y^2 = 4ax \) meets the parabola again at '\( t_2 \)', then prove that \[ t_2 = -\left( t_1 + \frac{2}{t_1} \right) \].
The normal at \( t_1 \) is:
\[ y = -t_1x + 2at_1 + at_1^3 \]
This normal meets the parabola again at \( t_2 \), so:
\[ at_2^2 = -t_1(2at_2) + 2at_1 + at_1^3 \]