A rod of length 12 cm moves with its ends always touching the coordinate axes. Determine the equation of the locus of a point P on the rod, which is 3 cm from the end in contact with the x-axis.
Solution and Explanation
Let AB be the rod making an angle \(θ\) with OX and P (x, y) be the point on it such that AP = 3 cm.
Then, \(PB = AB - AP = (12 - 3) cm = 9 cm [AB = 12 cm] \)
From P, draw \(PQ⊥OY\) and \(PR⊥OX.\)
In \( \triangle PBQ, cos θ = \frac{PQ}{PB} = \frac{x}{9}\)
In \(\triangle PRA, Sin θ =\frac{ PR}{PA} =\frac{ y}{3}\)
Since, \(sin^2 θ +cos^2 θ = 1,\)
\((\frac{y}{3})^2 + (\frac{x}{9})^2 = 1\)
or \(\frac{x^2}{81} + \frac{y^2}{9} = 1\)
Thus, the equation of the locus of point P on the rod is \(\frac{x^2}{81} + \frac{y^2}{9} = 1\)
Top Questions on Conic sections
- Consider the ellipse \(\frac{x^2}{9}+\frac{y^2}{4}=1\). Let S (p, q) be a point in the first quadrant such that \(\frac{p^2}{9}+\frac{q^2}{4}>1\). Two tangents are drawn from S to the ellipse, of which one meets the ellipse at one end point of the minor axis and the other meets the ellipse at a point T in the fourth quadrant. Let R be the vertex of the ellipse with positive x-coordinate and Obe the center of the ellipse. If the area of the triangle △ORT is \(\frac{3}{2}\) , then which of the following options is correct ?
- JEE Advanced - 2024
- Mathematics
- Conic sections
- The sum of squares of all possible values of $k$, for which the area of the region bounded by the parabolas \[2y^2 = kx \quad \text{and} \quad ky^2 = 2(y - x)\]is maximum, is equal to:
- JEE Main - 2024
- Mathematics
- Conic sections
- Let a conic \( C \) pass through the point \( (4, -2) \) and \( P(x, y), \, x \geq 3 \), be any point on \( C \). Let the slope of the line touching the conic \( C \) only at a single point \( P \) be half the slope of the line joining the points \( P \) and \( (3, -5) \). If the focal distance of the point \( (7, 1) \) on \( C \) is \( d \), then \( 12d \) equals ______.
- JEE Main - 2024
- Mathematics
- Conic sections
- Let \(S\) be the focus of the hyperbola \(\frac{x^2}{3} - \frac{y^2}{5} = 1\), on the positive x-axis. Let \(C\) be the circle with its centre at \(A\left(\sqrt{6}, \sqrt{5}\right)\) and passing through the point \(S\). If \(O\) is the origin and \(SAB\) is a diameter of \(C\), then the square of the area of the triangle \(OSB\) is equal to -
- JEE Main - 2024
- Mathematics
- Conic sections
- The parabola \( y^2 = 4x \) divides the area of the circle \( x^2 + y^2 = 5 \) in two parts. The area of the smaller part is equal to:
- JEE Main - 2024
- Mathematics
- Conic sections
Questions Asked in CBSE Class XI exam
- Draw formulas for the first five members of each homologous series beginning with the following compounds.\((a) H–COOH (b) CH_3COCH_3 (c) H–CH=CH_2\)
- CBSE Class XI
- Organic Chemistry- Some Basic Principles and Techniques
- Distinguish between the following pairs of sentences.
(i) He was visibly moved.
(ii) He was visually impaired.- CBSE Class XI
- The adventure
- How, according to you, can peace and liberty be maintained in a state?
- CBSE Class XI
- The tale of melon City
Figures 9.20(a) and (b) refer to the steady flow of a (non-viscous) liquid. Which of the two figures is incorrect ? Why ?
- CBSE Class XI
- Pressure
- Describe the change in hybridisation (if any) of the Al atom in the following reaction.
\(AlCl_3+Cl^- \rightarrow AlCl_4^-\)- CBSE Class XI
- Hybridisation
Concepts Used:
Conic Sections
When a plane intersects a cone in multiple sections, several types of curves are obtained. These curves can be a circle, an ellipse, a parabola, and a hyperbola. When a plane cuts the cone other than the vertex then the following situations may occur:
Let ‘β’ is the angle made by the plane with the vertical axis of the cone
- When β = 90°, we say the section is a circle
- When α < β < 90°, then the section is an ellipse
- When α = β; then the section is said to as a parabola
- When 0 ≤ β < α; then the section is said to as a hyperbola
Read More: Conic Sections