Find the coordinates of the foot of the perpendicular drawn from

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 Multiple Choice QuestionsShort Answer Type

151. Find equation of a plane parallel to 2x – 3y + z + 9 = 0 and also passing through origin.  
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152. Find the equation of the plane through P (1, 4, – 2) that is parallel to the plane – 2 x + y – 3 z = 0.
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153.

Find equation of the plane parallel to x + 3y – 2z + 7 = 0 and passing through the origin.   

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154. Find equation of a plane parallel to 3x – 2y + z – 11= 0 and passing through the origin. 
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155. Find the equation of the plane through the point (3, 4,–1) which is parallel to the plane straight r with rightwards arrow on top. space open parentheses 2 straight i with hat on top space minus space 3 space straight j with hat on top space plus space 5 space straight k with hat on top close parentheses space plus space 7 space equals space 0.
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156. Find the equation of the plane passing through (a, b, c) and parallel to the plane
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 Multiple Choice QuestionsLong Answer Type

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157. Find the coordinates of the foot of the perpendicular drawn from the origin to the plane 2x – 3y + 4z – 6 = 0.


The equation of plane is
2x – 3y + 4z – 6 = 0    ...(1)
Direction ratios of the normal to the plane (1) are 2, –3, 4.
Dividing each by square root of left parenthesis 2 right parenthesis squared plus left parenthesis negative 3 right parenthesis squared plus left parenthesis 4 right parenthesis squared end root space equals space square root of 4 plus 9 plus 16 end root space equals square root of 29 comma we get the direction cosines of the normal as fraction numerator 2 over denominator square root of 29 end fraction comma space minus fraction numerator 3 over denominator square root of 29 end fraction comma space fraction numerator 4 over denominator square root of 29 end fraction.
∴ dividing (1) throughout by square root of 29 comma we get, fraction numerator 2 over denominator square root of 29 end fraction straight x plus fraction numerator negative 3 over denominator square root of 29 end fraction straight y plus fraction numerator 4 over denominator square root of 29 end fraction straight z space equals space fraction numerator 6 over denominator square root of 29 end fraction
This is of the form l x + m y + n z = p, where p is the distance of the plane from the origin.
therefore distance of plane from the origin = fraction numerator 6 over denominator square root of 29 end fraction.
Let (x1, y1, z1) be the coordinates of the foot of perpendicular drawn from origin 0(0, 0, 0) to the plane (1).


∴ direction ratios of OP are .x1– 0, y, –0, –0 i.e. x1, y1, z1
∴  Direction cosines of OP are
fraction numerator 2 over denominator square root of 29 end fraction comma space space minus fraction numerator 3 over denominator square root of 29 end fraction comma space fraction numerator 4 over denominator square root of 29 end fraction

Since direction cosines and direction ratios of a line are proportional
therefore space space space space fraction numerator straight x subscript 1 over denominator begin display style fraction numerator 2 over denominator square root of 29 end fraction end style end fraction space space equals space fraction numerator straight y subscript 1 over denominator negative begin display style fraction numerator 3 over denominator square root of 29 end fraction end style end fraction space equals space fraction numerator straight z subscript 1 over denominator begin display style fraction numerator 4 over denominator square root of 29 end fraction end style end fraction space equals space straight k
therefore space space space space space space space space space space space straight x subscript 1 space equals space fraction numerator 2 space straight k over denominator square root of 29 end fraction comma space space space space space straight y subscript 1 space equals space minus fraction numerator 3 space straight k over denominator square root of 29 end fraction comma space space space straight z subscript 1 space equals space fraction numerator 4 space straight k over denominator square root of 29 end fraction


Since P(x1, y1, z1) lies on plane (1)
therefore space space space space space 2 cross times fraction numerator 2 space straight k over denominator square root of 29 end fraction space minus 3 cross times fraction numerator negative 3 space straight k over denominator square root of 29 end fraction plus 4 cross times fraction numerator 4 straight k over denominator square root of 29 end fraction space equals 6
therefore space 4 space straight k space plus space 9 space straight k space plus space 16 space straight k space equals space 6 space square root of 29 space space space rightwards double arrow space space space 29 space straight k space equals space 6 square root of 29 space space space rightwards double arrow space space space straight k space equals fraction numerator 6 over denominator square root of 29 end fraction
therefore space space space space space space space straight x subscript 1 space equals space fraction numerator 2 over denominator square root of 29 end fraction cross times fraction numerator 6 over denominator square root of 29 end fraction space equals space 12 over 29 comma space space space straight y subscript 1 space equals space minus fraction numerator 3 over denominator square root of 29 end fraction cross times fraction numerator 6 over denominator square root of 29 end fraction space equals space minus 18 over 29 comma
space space space space space space space space space space space space straight z subscript 1 space equals space fraction numerator 4 over denominator square root of 29 end fraction cross times fraction numerator 6 over denominator square root of 29 end fraction space equals space 24 over 29
therefore space space space foot space of space perpendicular space is space space open parentheses 12 over 29 comma space minus 18 over 29 comma space 24 over 29 close parentheses

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 Multiple Choice QuestionsShort Answer Type

158. Find the distance of the plane 2x – 3 y + 4 z – 6 = 0 from the origin.
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159.

In each of the following cases, determine the direction cosines of the normal to the plane and the distance from the origin.
z = 2

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160.

In each of the following cases, determine the direction cosines of the normal to the plane and the distance from the origin.
x + y + z = 1

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