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Three Dimensional Geometry

Question
CBSEENMA12033430

Find the equation of the plane passing through the points (0. – 1, 0), (1, 1, 1) and (3, 3,0).

Solution

The equation of any plane through the points (0, – 1, 0) is
a (x – 0) + b (y + 1) + c (z – 0) = 0    ...(1)
∴ it passes through (1, 1, 1)
∴ a + 2 b + c = 0        ...(2)
Again plane passes through (3, 3, 0)
∴ 3 a + 4 b + 0 c = 0    ...(3)
Solve (2) and (3), we get,
                fraction numerator straight a over denominator 0 minus 4 end fraction space equals fraction numerator straight b over denominator 3 minus 0 end fraction space equals fraction numerator straight c over denominator 4 minus 6 end fraction
therefore space space space space space space space fraction numerator straight a over denominator negative 4 end fraction space equals space straight b over 3 space equals space fraction numerator straight c over denominator negative 2 end fraction space space space space space space space space space space space space space space or space space space space space space straight a over 4 space equals space fraction numerator straight b over denominator negative 3 end fraction space equals space straight c over 2 space equals space straight k space space space space space left parenthesis say right parenthesis
therefore space space space space space straight a space equals space 4 space straight k comma space space space space straight b space equals space minus 3 space straight k comma space space space space straight c space equals space 2 space straight k
Putting values of a, b,c in (1), we get,
4 k x – 3 k (y + 1) + 2 k z = 0
or 4 x – 3 y + 2 z = 3
which is required equation of plane.

Some More Questions From Three Dimensional Geometry Chapter

Find the direction cosines of x, y and z-axis.