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Find the image of the point : (i) (2,-...

Find the image of the point :
(i) (2,-3,2) in the plane 2x + y - 3z = 10
(ii) (1,2,3) in the plane x + 2y + 4z = 38
(iii) (2,-1,3) in the plane 3x - 2y - z = 9.

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To find the image of a point in a given plane, we can follow these steps: ### Step-by-Step Solution: #### (i) Finding the image of the point (2, -3, 2) in the plane \(2x + y - 3z = 10\) 1. **Identify the point and the plane equation**: - Point \( P(2, -3, 2) \) - Plane equation: \( 2x + y - 3z = 10 \) 2. **Find the normal vector of the plane**: - The normal vector \( \mathbf{n} \) can be derived from the coefficients of \( x, y, z \) in the plane equation: \[ \mathbf{n} = (2, 1, -3) \] 3. **Find the foot of the perpendicular from point P to the plane**: - The formula for the foot of the perpendicular from point \( P(x_1, y_1, z_1) \) to the plane \( Ax + By + Cz + D = 0 \) is given by: \[ \left( x_1 - \frac{A \cdot D}{A^2 + B^2 + C^2}, y_1 - \frac{B \cdot D}{A^2 + B^2 + C^2}, z_1 - \frac{C \cdot D}{A^2 + B^2 + C^2} \right) \] - Rearranging the plane equation gives \( D = -10 \). Thus, we have: \[ A = 2, B = 1, C = -3, D = -10 \] - Calculate \( A^2 + B^2 + C^2 \): \[ A^2 + B^2 + C^2 = 2^2 + 1^2 + (-3)^2 = 4 + 1 + 9 = 14 \] - Now, substituting into the foot of the perpendicular formula: \[ \text{Foot} = \left( 2 - \frac{2 \cdot (-10)}{14}, -3 - \frac{1 \cdot (-10)}{14}, 2 - \frac{-3 \cdot (-10)}{14} \right) \] - Simplifying gives: \[ \text{Foot} = \left( 2 + \frac{20}{14}, -3 + \frac{10}{14}, 2 - \frac{30}{14} \right) = \left( 2 + \frac{10}{7}, -3 + \frac{5}{7}, 2 - \frac{15}{7} \right) \] - Thus, the foot of the perpendicular is: \[ \left( \frac{24}{7}, -\frac{16}{7}, -\frac{1}{7} \right) \] 4. **Find the image point**: - The image point \( I \) can be found using the midpoint formula: \[ I = (2 \cdot \text{Foot} - P) \] - Calculating gives: \[ I = \left( 2 \cdot \frac{24}{7} - 2, 2 \cdot -\frac{16}{7} + 3, 2 \cdot -\frac{1}{7} - 2 \right) \] - Simplifying: \[ I = \left( \frac{48}{7} - \frac{14}{7}, -\frac{32}{7} + \frac{21}{7}, -\frac{2}{7} - \frac{14}{7} \right) = \left( \frac{34}{7}, -\frac{11}{7}, -\frac{16}{7} \right) \] #### (ii) Finding the image of the point (1, 2, 3) in the plane \(x + 2y + 4z = 38\) 1. **Identify the point and the plane equation**: - Point \( P(1, 2, 3) \) - Plane equation: \( x + 2y + 4z = 38 \) 2. **Find the normal vector of the plane**: - Normal vector \( \mathbf{n} = (1, 2, 4) \) 3. **Find the foot of the perpendicular from point P to the plane**: - Rearranging gives \( D = -38 \). - Calculate \( A^2 + B^2 + C^2 \): \[ A^2 + B^2 + C^2 = 1^2 + 2^2 + 4^2 = 1 + 4 + 16 = 21 \] - Foot of the perpendicular: \[ \text{Foot} = \left( 1 - \frac{1 \cdot (-38)}{21}, 2 - \frac{2 \cdot (-38)}{21}, 3 - \frac{4 \cdot (-38)}{21} \right) \] - Simplifying gives: \[ \text{Foot} = \left( 1 + \frac{38}{21}, 2 + \frac{76}{21}, 3 + \frac{152}{21} \right) = \left( \frac{59}{21}, \frac{118}{21}, \frac{215}{21} \right) \] 4. **Find the image point**: - The image point \( I \): \[ I = (2 \cdot \text{Foot} - P) \] - Calculating gives: \[ I = \left( 2 \cdot \frac{59}{21} - 1, 2 \cdot \frac{118}{21} - 2, 2 \cdot \frac{215}{21} - 3 \right) \] - Simplifying: \[ I = \left( \frac{118}{21} - \frac{21}{21}, \frac{236}{21} - \frac{42}{21}, \frac{430}{21} - \frac{63}{21} \right) = \left( \frac{97}{21}, \frac{194}{21}, \frac{367}{21} \right) \] #### (iii) Finding the image of the point (2, -1, 3) in the plane \(3x - 2y - z = 9\) 1. **Identify the point and the plane equation**: - Point \( P(2, -1, 3) \) - Plane equation: \( 3x - 2y - z = 9 \) 2. **Find the normal vector of the plane**: - Normal vector \( \mathbf{n} = (3, -2, -1) \) 3. **Find the foot of the perpendicular from point P to the plane**: - Rearranging gives \( D = -9 \). - Calculate \( A^2 + B^2 + C^2 \): \[ A^2 + B^2 + C^2 = 3^2 + (-2)^2 + (-1)^2 = 9 + 4 + 1 = 14 \] - Foot of the perpendicular: \[ \text{Foot} = \left( 2 - \frac{3 \cdot (-9)}{14}, -1 - \frac{-2 \cdot (-9)}{14}, 3 - \frac{-1 \cdot (-9)}{14} \right) \] - Simplifying gives: \[ \text{Foot} = \left( 2 + \frac{27}{14}, -1 - \frac{18}{14}, 3 - \frac{9}{14} \right) = \left( \frac{55}{14}, -\frac{32}{14}, \frac{33}{14} \right) \] 4. **Find the image point**: - The image point \( I \): \[ I = (2 \cdot \text{Foot} - P) \] - Calculating gives: \[ I = \left( 2 \cdot \frac{55}{14} - 2, 2 \cdot -\frac{32}{14} + 1, 2 \cdot \frac{33}{14} - 3 \right) \] - Simplifying: \[ I = \left( \frac{110}{14} - \frac{28}{14}, -\frac{64}{14} + \frac{14}{14}, \frac{66}{14} - \frac{42}{14} \right) = \left( \frac{82}{14}, -\frac{50}{14}, \frac{24}{14} \right) \] ### Final Results: - (i) The image of the point (2, -3, 2) in the plane \(2x + y - 3z = 10\) is \(\left( \frac{34}{7}, -\frac{11}{7}, -\frac{16}{7} \right)\). - (ii) The image of the point (1, 2, 3) in the plane \(x + 2y + 4z = 38\) is \(\left( \frac{97}{21}, \frac{194}{21}, \frac{367}{21} \right)\). - (iii) The image of the point (2, -1, 3) in the plane \(3x - 2y - z = 9\) is \(\left( \frac{82}{14}, -\frac{50}{14}, \frac{24}{14} \right)\).
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MODERN PUBLICATION-THREE DIMENSIONAL GEOMETRY -EXERCISE 11 (E) (LONG ANSWER TYPE QUESTIONS (II) )
  1. (i) Find the distance of the point (-2,3,-4) from the line : (x + 2)...

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  2. Find the ratio in which the line-segment joining the points : (i) (2...

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  3. Find the equation of the plane passing through the point (1,2,1) and p...

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  4. Find the image of the point : (i) (2,-3,2) in the plane 2x + y - 3z ...

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  5. (i) Find the co-ordinates of foot of perpendicular drawn from the poin...

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  6. The foot of the perpendicular drawn from origin to a plane is (4,-2,5)...

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  7. Find the co-ordinates of the foot of the perpendicular Q drawn from P ...

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  8. Find the length and the foot of the perpendicular from the point P(7,1...

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  9. Find the distance of the point P (1,2,3) from its image in the plane x...

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  10. Find the coordinates of the point where the line through (3,-4,-5) and...

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  11. (i) A variable plane, which remains at a constant distance '3p' from t...

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  12. If a plane has intercepts a,b,c on axes and is at a distance of p unit...

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  13. A variable plane passes through a fixed point (a,b,c) and meets the co...

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  14. A variable plane moves in such a way that the sum of the reciprocals o...

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  15. Differentiate e^tanx cosx

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  16. Find the equations of the bisectors of the angles between the plane...

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  17. In the following determine whether the given planes are parallel or pe...

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