JEE Main 2023
Conic Sections
Parabola
Hard
Question
The equations of two sides of a variable triangle are and , and its third side is a tangent to the parabola . The locus of its circumcentre is :
Options
Solution
This problem requires us to find the locus of the circumcenter of a variable triangle. The key to solving it involves understanding the properties of tangents to a parabola, determining the triangle's vertices, and recognizing the special case of a right-angled triangle's circumcenter.
1. Key Concepts and Formulas
- Equation of a Tangent to a Parabola: For a parabola of the form , the equation of a tangent line in parametric form (using parameter ) is given by This form is particularly useful as it allows us to represent the varying third side of the triangle using a single parameter.
- Vertices of a Triangle: These are the points where the three side equations intersect. We will find these by