Get Answers to all your Questions

header-bg qa

Need solution for RD sharma maths class 12 chapter 28 The Plane exercise 28.8 question 15

Answers (1)

The answer of the given question is  7x-5y+4z-8=0.

Hint:-  We know that, equation of a plane passing through the line of intersection of two planes

  a_{1}x+b_{1}y+c_{1}z+d_{1}=0 and a_{2}x+b_{2}y+c_{2}z+d_{2}=0 is given by

\left (a_{1}x+b_{1}y+c_{1}z+d_{1} \right )+k\left ( a_{2}x+b_{2}y+c_{2}z+d_{2} \right )=0

Given:- 3x-y+2z=4 and x+y+z=2 , Point (2,2,1)

Solution:- The equation of any plane through the intersection of the planes is

3x-y+2z-4=0  and  x+y+z-2=0 is

\left (3x-y+2z-4 \right )+\alpha \left (x+y+z-2 \right )=0 , where \alpha \in \mathbb{R}                   …(i)

The plane passes through the point (2, 2,1). Therefore, this point will satisfy equation (1)

\therefore \left (3 \times 2-2+2 \times 1-4 \right )+\alpha \left (2+2+1-2 \right )=0\\ 2+3\alpha =0\\ \alpha =-\frac{2}{3}

Substituting \alpha =-\frac{2}{3} in equation (i), we obtain
\left (3x-y+2z-4 \right )-\frac{3}{2}\left (x+y+z-2 \right )=0\\ 3\left (3x-y+2z-4 \right )-2\left (x+y+z-2 \right )=0\\ \left (9x-3y+6z-12 \right )-2\left (x+y+z-2 \right )=0\\ 7x-5y+4z-8=0

Posted by

Info Expert 29

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads