The distance of the point (2,1,-1) from the plane `x-2y+4z=9` is (A) `sqrt(13)/21` (B) `13/21` (C) `13/sqrt(21)` (D) `sqrt(13/21)`

The inverse of the matrix ([2,1],[1,3]) is

If A(1,-1,2),B(2,1,-1)C(3,-1,2) are the vertices of a triangle then the area of triangle ABC is (A) sqrt(12) (B) sqrt(3) (C) sqrt(5) (D) sqrt(13)

The distance of (0,0) from 2x-3y+5=0 measured parallel to the line 3x-2y=1=0 is (5)/(sqrt(13)) b.(4)/(sqrt(13)) c.sqrt(13) d.none of these

The length of perpendicular from the poit (1,-1,2) on the line (x+1)/2=(2-y)/3=(z+2)/4 is (A) 0 (B) sqrt(6) (C) sqrt(21) (D) none of these

The distance of the point (1,0,2) from the point of intersection of the line (x-2)/(3)=(y+1)/(4)=(z-2)/(12) and the plane x?y+z=16, is : (1)2sqrt(14)(2)8(3)3sqrt(21)(4)27

Distance between parallel lines 4x+6y+8=0, 6x+9y+15=0 is (i) 2/sqrt13 (ii) 1/sqrt13 (iii) 3/sqrt13 (iv) 4/sqrt13

(1)/(sqrt(21+4x-x^(2)))

The length of the chord of the parabola y^(2)=x which is bisected at the point (2,1) is (a) 2sqrt(3)( b) 4sqrt(3)(c)3sqrt(2) (d) 2sqrt(5)

The centre and radius of the spehere x^2+y^2+z^2=3x-4z+1=0 are (A) (-3/2, 0, -2),sqrt(21)/2 (B) (-3/2, 0, 2),sqrt(21)/2 (C) (-3/2, 0, -2),sqrt(21)/2 (D) (-3/2, 2, 0),21/2