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Three Dimensional Geometry

Question
CBSEENMA12033512

Show that the plane whose vector equation is straight r with rightwards arrow on top. space open parentheses straight i with hat on top space plus space 2 space straight j with hat on top space minus space straight k with hat on top close parentheses space equals 3 contains the line whose vector equation is straight r with rightwards arrow on top space equals space straight i with hat on top space plus space straight j with hat on top space plus space straight lambda open parentheses 2 straight i with hat on top space plus space straight j with hat on top space plus space 4 space straight k with hat on top close parentheses

Solution
The equation of given plane is
straight r with rightwards arrow on top. space open parentheses straight i with hat on top space plus space 2 space straight j with hat on top space minus space straight k with hat on top close parentheses space equals space 3                                       ...(1)
The equation of given plane is
 straight r with rightwards arrow on top space equals space straight i with hat on top space plus space straight j with hat on top space plus space straight lambda space open parentheses 2 straight i with hat on top space plus space straight j with hat on top space plus space 4 space straight k with hat on top close parentheses                     ...(2)
Now line (2) passes through the point (1, 1, 0) with position vector straight i with hat on top space plus space straight j with hat on top and is parallel to the vector 2 space straight i with hat on top space plus space straight j with hat on top space plus space 4 space straight k with hat on top.
Now plane (1) passes through the point with position vector straight i with hat on top space plus space straight j with hat on top
if   open parentheses straight i with hat on top space plus space straight j with hat on top close parentheses space. space open parentheses straight i with hat on top space plus space 2 space straight j with hat on top space minus space straight k with hat on top close parentheses space equals space 3
i.e.   if  1 + 2 -0 = 3
i.e.  if 3 = 3,  which is true
Now, straight i with hat on top space plus space 2 space straight j with hat on top space minus space straight k with hat on top is a vector normal to the plane (1). It will be perpendicular to the line (2) if it is perpendicular to 2 space straight i with hat on top space plus space straight j with hat on top space plus space 4 space straight k with hat on top
i.e.  if  open parentheses straight i with hat on top space plus space 2 space straight j with hat on top space minus space straight k with hat on top close parentheses. space space space open parentheses 2 space straight i with hat on top space plus space straight j with hat on top space plus space space 4 space straight k with hat on top close parentheses space equals space 0
i.e. if 2 + 2 – 4 = 0
i.e. if 0 = 0, which is true
∴  plane (1) contains the line (2 )

Some More Questions From Three Dimensional Geometry Chapter

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