MHT CET202314 May 2023Evening ShiftMathematicsThree Dimensional GeometryActual
The mirror image of P (2,4,-1) in the plane x-y+2 z-2=0 is ( a , b , c ) , then the value of a + b + c is
Options
- A4
- B5
- C7
- D9
Correct answer
D. 9
Step-by-step solution
The d.r.s. of the normal to the plane are 1,-1,2 . The equation of line PM is aligned & x-2 1 = y-4 -1 = z +1 2 = ( say ) & x= +2, y=- +4, z =2 -1 & Let M ( +2,- +4,2 -1) aligned array ll & Equation of plane becomes & 1( +2)-1(- +4)+2(2 -1)-2=0 & =1 & M (3,3,1) array Since M is the mid-point of P Q . aligned & 2+ a 2 =3, 4+ b 2 =3, -1+ c 2 =1 & a =4, ~b =2, c =3 & a + b + c =9 aligned