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Three Dimensional Geometry

Question
CBSEENMA12035893

Find the equation of the plane passing through the point (-1, 3, 2) and perpendicular to each of the planes x + 2y + 3z = 5 and 3x + 3y + z = 0.

Solution

Let the equation of the plane be,

A ( x - x1 ) + B ( y - y1 ) + C ( z - z1 ) = 0

Plane passes throughthe points ( -1, 3, 2 )

 A ( x + 1 ) + B ( y - 3 ) + C ( z - 2 ) = 0          ........(i)

Now applying the condition of perpendicularity to the plane (i) with planes

x + 2y + 3z = 5  and   3x + 3y + z = 0, We have,

A + 2B + 3C = 0

3A + 3B + C = 0 

Solving we get

A + 2B + 3C = 0

9A + 9B + 3C = 0 

By cross multiplication, we have,

A2 x 3 - 9 x 3 = B9 x 3 - 1 x 3 = C1 x 9 - 2 x 9 A6- 27 = B27 - 3 = C9 - 18 A- 21 = B24 = C- 9 A- 7 = B8 = C- 3 A = 7 λ;    B = - 8 λ;   C = 3 λ

By substituting A and C in equation (i), we get,

Substituting the values of A, B and C in equation (i), we have,

7 λ ( x + 1 ) - 8 λ ( y - 3 ) + 3 λ ( z - 2  ) =0 7x + 7 - 8y + 24 + 3z - 6 = 0 7x - 8y + 3z +25 = 0

Some More Questions From Three Dimensional Geometry Chapter

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