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If a point P is taken on xy=2 and then a...

If a point `P` is taken on `xy=2` and then a normal is drawn from `P` on the ellipse `(x^(2))/6+(y^(2))/3=1` which is perpendicular to `x+y=8`, then `P` is

A

`(1,2)`

B

`(-1,-2)`

C

`(2,1)`

D

`(-2,-1)`

Text Solution

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To solve the problem step-by-step, we need to find the point \( P \) on the hyperbola defined by \( xy = 2 \) such that the normal drawn from \( P \) to the ellipse defined by \( \frac{x^2}{6} + \frac{y^2}{3} = 1 \) is perpendicular to the line \( x + y = 8 \). ### Step 1: Define the Point \( P \) Let the coordinates of point \( P \) be \( (h, \frac{2}{h}) \) since \( P \) lies on the curve \( xy = 2 \). **Hint:** Use the relationship \( xy = 2 \) to express one variable in terms of the other. ### Step 2: Find the Slope of the Line \( x + y = 8 \) The line \( x + y = 8 \) can be rewritten in slope-intercept form as \( y = -x + 8 \). The slope \( m_1 \) of this line is \( -1 \). **Hint:** Convert the line equation to slope-intercept form to easily identify the slope. ### Step 3: Determine the Slope of the Normal Since the normal to the ellipse is perpendicular to the line \( x + y = 8 \), the slope \( m_2 \) of the normal must satisfy: \[ m_1 \cdot m_2 = -1 \implies -1 \cdot m_2 = -1 \implies m_2 = 1 \] **Hint:** Use the property of perpendicular lines where the product of their slopes equals -1. ### Step 4: Write the Equation of the Normal The equation of the normal to the ellipse at a point \( (x_0, y_0) \) can be expressed as: \[ y - y_0 = m_2 (x - x_0) \] Substituting \( m_2 = 1 \) gives: \[ y - y_0 = (x - x_0) \] Rearranging, we have: \[ y = x - x_0 + y_0 \] **Hint:** Remember that the slope of the normal is the negative reciprocal of the slope of the tangent. ### Step 5: Find the Coordinates of the Point on the Ellipse For the ellipse \( \frac{x^2}{6} + \frac{y^2}{3} = 1 \), the coordinates of the point on the ellipse can be expressed in parametric form as: \[ (x_0, y_0) = (\sqrt{6} \cos \theta, \sqrt{3} \sin \theta) \] **Hint:** Use parametric equations to express points on the ellipse. ### Step 6: Set Up the Equation for the Normal The slope of the normal at the point \( (x_0, y_0) \) is given by: \[ \text{slope of normal} = -\frac{\sqrt{6} \sec \theta}{-\sqrt{3}} = \frac{\sqrt{6}}{\sqrt{3}} \sec \theta = \sqrt{2} \sec \theta \] Setting this equal to \( 1 \) gives: \[ \sqrt{2} \sec \theta = 1 \implies \sec \theta = \frac{1}{\sqrt{2}} \implies \cos \theta = \frac{1}{\sqrt{2}} \implies \theta = \frac{\pi}{4} \] **Hint:** Use trigonometric identities to relate the slopes. ### Step 7: Substitute \( \theta \) Back to Find \( P \) Substituting \( \theta = \frac{\pi}{4} \) into the parametric equations gives: \[ x_0 = \sqrt{6} \cdot \frac{1}{\sqrt{2}} = \sqrt{3}, \quad y_0 = \sqrt{3} \cdot \frac{1}{\sqrt{2}} = \frac{3}{2} \] Now, we need to relate this back to \( P \): \[ h = \sqrt{3}, \quad \frac{2}{h} = \frac{2}{\sqrt{3}} \] **Hint:** Use the values of \( x_0 \) and \( y_0 \) to find \( h \) and subsequently the coordinates of \( P \). ### Step 8: Solve for \( h \) We can find \( h \) by solving the equation: \[ h - \frac{2}{h} = 1 \implies h^2 - h - 2 = 0 \] Factoring gives: \[ (h - 2)(h + 1) = 0 \implies h = 2 \text{ or } h = -1 \] **Hint:** Use the quadratic formula or factoring to solve for \( h \). ### Step 9: Find the Corresponding Points \( P \) For \( h = 2 \): \[ P_1 = (2, 1) \] For \( h = -1 \): \[ P_2 = (-1, -2) \] **Hint:** Substitute the values of \( h \) back into the expression for \( P \). ### Final Answer The points \( P \) are \( (2, 1) \) and \( (-1, -2) \). The valid point \( P \) that satisfies all conditions is: \[ \boxed{(2, 1)} \]

To solve the problem step-by-step, we need to find the point \( P \) on the hyperbola defined by \( xy = 2 \) such that the normal drawn from \( P \) to the ellipse defined by \( \frac{x^2}{6} + \frac{y^2}{3} = 1 \) is perpendicular to the line \( x + y = 8 \). ### Step 1: Define the Point \( P \) Let the coordinates of point \( P \) be \( (h, \frac{2}{h}) \) since \( P \) lies on the curve \( xy = 2 \). **Hint:** Use the relationship \( xy = 2 \) to express one variable in terms of the other. ### Step 2: Find the Slope of the Line \( x + y = 8 \) ...
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