1.

The distance of the point `(1,3,-7)`from the plane passing through the point `(1,-1,-1),`having normal perpendicular to both the lines`(x-1)/1=(y+2)/(-2)=(z-4)/3a n d(x-2)/2=(y+1)/(-1)=(z+7)/(-1)i s:``5/(sqrt(83))`(2) `(10)/(sqrt(74))`(3) `(20)/(sqrt(74))`(4) `(10)/(sqrt(83))`A. `(20)/(sqrt(74))`unitsB. `(10)/(sqrt(83))` unitsC. `(5)/(sqrt(83))`unitsD. `(10)/(sqrt(74))`units

Answer» Correct Answer - B
Given, equations of lines are
`(x-1)/(1)=(y+2)/(-2)=(z-4)/(3)`
and`" "(x-2)/(2)=(y+1)/(-1)=(z+7)/(-1)`
Let `n_(1)=hati-2hatj+3hatk` and `n_(2)=2hati-hatj-hatk`
`:.` Any vector n perpendicular to both `n_(1),n_(2)` is given by
`n=n_(1)xxn_(2)`
`implies" "n=|{:(hati,hatj,hatk),(1,-2,3),(2,-1,-2):}|=5hati+7hatj+3hatk`
`:.` Eauation of a plane passing through (1,-1,-1) and perpendicular to n is given by
`5(x-1)+7(y+1)+3(z+1)=0`
`implies" "5x+7y+3z+5=0`
`:.` Required distance`=|(5+21-21+5)/(sqrt(5^(2)+7^(2)+3^(2)))|=(10)/(sqrt(83))` units


Discussion

No Comment Found

Related InterviewSolutions