Question:

The two tangents to the curve \(ax^2 + 2hxy + by^2 = 1\), \(a>0\) at the points, where it crosses X-axis, are

Show Hint

If the curve is symmetric about the origin, slopes at symmetric points are equal.
Updated On: Apr 20, 2026
  • parallel
  • perpendicular
  • inclined at an angle \(\frac{\pi}{4}\)
  • None of these
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is A

Solution and Explanation

To solve this problem, we need to determine the nature of the tangents to the given conic section equation at the points where it crosses the X-axis.

The curve is given by the equation \(ax^2 + 2hxy + by^2 = 1\). This equation represents a general conic section. 

The condition for the curve to cross the X-axis is \(y = 0\). Substituting \(y=0\) into the equation gives us:

\(ax^2 = 1 \Rightarrow x^2 = \frac{1}{a}\)

Thus, the points where the curve crosses the X-axis are \((x_1, 0)\) and \((x_2, 0)\) where \(x_1 = \frac{1}{\sqrt{a}}\) and \(x_2 = -\frac{1}{\sqrt{a}}\).

Now, we find the equation of the tangents at these points. The general formula for the tangent to a conic \(ax^2 + 2hxy + by^2 = 1\) at a point \((x_1, y_1)\) is:

\(axx_1 + h(xy_1 + yx_1) + byy_1 = 1\).

For the point \((x_1, 0)\): Substitute \(y_1 = 0\), the tangent equation becomes:

\(axx_1 = 1\)

For the point \((x_2, 0)\): Substitute \(y_1 = 0\), the tangent equation becomes:

\(axx_2 = 1\)

Both equations are of the form \(axx_1 = 1\) and \(ax(-x_1) = 1\) respectively.

These equations show that both tangents are vertical lines, which means they are parallel to each other. Therefore, the two tangents at the points where the curve crosses the X-axis are parallel.

Hence, the correct answer is: Parallel.

Was this answer helpful?
0
0