Q:- Two systems of rectangular axes have the same origin. If a plane cuts them at distances a,b,c and a1,b1,c1 from the origin, thenA.(1/a^2)+(1/b^2)+(1/c^2)=(1/a1^2)+(1/b1^2)+(1/c1^2)B.(1/a^2)-(1/b^2)+(1/c^2)=(1/a1^2)-(1/b1^2)+(1/c1^2)C. (a^2)+(b^2)+(c^2)=(a1^2)+(b1^2)+(c1^2)D.(a^2)-(b^2)+(c^2)=(a1^2)-(b1^2)+(c1^2)

Dear Tapasranjan

equation of planes are 

x/a + y/b + z/c =1

and

 x/a1  + y/b1 + z/c1 =1

since the axis is roatated but the origin and the plane is same so perpendicular distance from the origine to both the plave will be same

|1|/√{1/a² + 1/b² +1/c²}  = |1|/√{1/a1² + 1/b1² +1/c1²}

or

 √{1/a² + 1/b² +1/c²}  = √{1/a1² + 1/b1² +1/c1²}

or

1/a² + 1/b² +1/c²  = 1/a1² + 1/b1² +1/c1²

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