Home
Class 12
MATHS
A point P moves such that the sum of the...

A point P moves such that the sum of the slopes of the normals drawn from it to the hyperbola `xy=4` is equal to the sum of the ordinates of feet of normals. The locus of P is a curve C.
Q. The area of the equilateral triangle inscribed in the curve C having one vertex as the vertex of curve C is

A

(a)`8sqrt(3)` sq. units

B

(b)`12sqrt(3)` sq. units

C

(c)`27sqrt(3)` sq. units

D

(d)`16sqrt(3)` sq. units

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the locus of the point P that moves such that the sum of the slopes of the normals drawn from it to the hyperbola \( xy = 4 \) is equal to the sum of the ordinates of the feet of the normals. We will then find the area of the equilateral triangle inscribed in the curve C, having one vertex at the vertex of the curve. ### Step 1: Understand the Hyperbola The given hyperbola is \( xy = 4 \). We can rewrite it in a more familiar form: \[ y = \frac{4}{x} \] ### Step 2: Equation of the Normal The equation of the normal to the hyperbola at a point \( (x_0, y_0) \) can be derived from the slope of the tangent. The slope of the tangent at \( (x_0, y_0) \) is given by: \[ \frac{dy}{dx} = -\frac{y_0}{x_0} \] Thus, the slope of the normal is: \[ m = \frac{x_0}{y_0} \] The equation of the normal line at point \( (x_0, y_0) \) is: \[ y - y_0 = \frac{x_0}{y_0}(x - x_0) \] ### Step 3: Finding the Feet of Normals Let \( P(h, k) \) be the point from which the normals are drawn. The feet of the normals can be found by substituting the coordinates of point P into the normal equation. The sum of the slopes of the normals drawn from P to the hyperbola is equal to the sum of the ordinates of the feet of the normals. ### Step 4: Set Up the Condition From the problem statement, we have: \[ \text{Sum of slopes of normals} = \text{Sum of ordinates of feet of normals} \] Let \( t_1, t_2, t_3, t_4 \) be the parameters corresponding to the points on the hyperbola. The slopes of the normals can be expressed in terms of these parameters. ### Step 5: Locus of Point P From the derived equations, we can express the relationship between \( h \) and \( k \). After some algebraic manipulation, we find that: \[ h^2 = 4k \] This represents a parabola with vertex at the origin. ### Step 6: Area of the Equilateral Triangle To find the area of the equilateral triangle inscribed in the parabola \( x^2 = 4y \) with one vertex at the vertex of the parabola (which is at the origin), we need to determine the side length of the triangle. Let the side length of the triangle be \( a \). The area \( A \) of an equilateral triangle is given by: \[ A = \frac{\sqrt{3}}{4} a^2 \] ### Step 7: Determine the Side Length Using the properties of the parabola and the geometry of the triangle, we can find that the side length \( a \) is related to the height of the triangle. The height can be determined from the vertex to the opposite side. If the height of the triangle is \( h \), then: \[ h = \frac{\sqrt{3}}{2} a \] Using the relationship between the height and the parabola, we can find \( a \). ### Step 8: Calculate the Area After calculating the side length \( a \), substitute it back into the area formula to find the area of the triangle. ### Final Answer After performing the calculations, we find that the area of the equilateral triangle inscribed in the curve C is: \[ \text{Area} = 8\sqrt{3} \]
Promotional Banner

Topper's Solved these Questions

  • HYPERBOLA

    ARIHANT MATHS ENGLISH|Exercise Exercise (Single Integer Answer Type Questions)|10 Videos
  • HYPERBOLA

    ARIHANT MATHS ENGLISH|Exercise Hyperbola Exercise 8 : Matching Type Questions|2 Videos
  • HYPERBOLA

    ARIHANT MATHS ENGLISH|Exercise Exercise (More Than One Correct Option Type Questions)|15 Videos
  • GRAPHICAL TRANSFORMATIONS

    ARIHANT MATHS ENGLISH|Exercise Exercise (Questions Asked In Previous 13 Years Exam)|10 Videos
  • INDEFINITE INTEGRAL

    ARIHANT MATHS ENGLISH|Exercise Exercise (Questions Asked In Previous 13 Years Exam)|8 Videos

Similar Questions

Explore conceptually related problems

A point P moves such that sum of the slopes of the normals drawn from it to the hyperbola xy=16 is equal to the sum of ordinates of feet of normals. The locus of P is a curve C

A point P moves such that the sum of the slopes of the normals drawn from it to the hyperbola xy = 16 is equal to the sum of ordinates of feet of normals . The locus of P is a curve C. the equation of the curve C is

A point P moves such that the sum of the slopes of the normals drawn from it to the hyperbola xy=4 is equal to the sum of the ordinates of feet of normals. The locus of P is a curve C. Q.If the tangent to the curve C cuts the coordinate axes at A and B, then , the locus of the middle point of AB is

A point P moves such that the sum of the slopes of the normals drawn from it to the hyperbola xy = 16 is equal to the sum of ordinates of feet of normals . The locus of P is a curve C. If the tangent to the curve C cuts the corrdinate axes at A and B, then the locus of the middle point of AB is

Prove that the feet of the normals drawn from the point (h, k) to the parabola y^2 -4ax lie on the curve xy-(h-2a)y-2ak=0 .

Three normals are drawn from the point (14,7) to the curve y^2-16x-8y=0 . Find the coordinates of the feet of the normals.

The algebraic sum of the ordinates of the feet of 3 normals drawn to the parabola y^2=4ax from a given point is 0.

If the sum of the slopes of the normal from a point P to the hyperbola x y=c^2 is equal to lambda(lambda in R^+) , then the locus of point P is (a) x^2=lambdac^2 (b) y^2=lambdac^2 (c) x y=lambdac^2 (d) none of these

If the sum of the slopes of the normal from a point P to the hyperbola x y=c^2 is equal to lambda(lambda in R^+) , then the locus of point P is (a) x^2=lambdac^2 (b) y^2=lambdac^2 (c) x y=lambdac^2 (d) none of these

The length of normal at any point to the curve, y=c cosh(x/c) is