The diection cosines of two lines are proportional to `(2,3,-6) and (3,-4,5),` then the acute angle between them is (A) `cos^-1{49/36}` (B) `cos^-1 {(18sqrt(2))/35}` (C) `96^0` (D) `cos^-1(18/35)`

If direction-cosines of two lines are proportional to 4,3,2 and 1, -2, 1, then the angle between the lines is :

If the direction ratios of two lines are (1,2,4) and (-1,-2,-3) then the acute angle between them is

The angle between the lines whose direction cosines are proportional to (1,2,1) and (2,-3,6) is

What is the angle between the lines whose direction cosines are proportional to (2,3,4) and (1,-2,1) respectively

What is the angle between the lines whose direction cosines are proportional to (2,3,4) and (1,-2,1) respectively?

What are the co-ordinates of the mid-point of A(1,4) and D(3,5) ?

The angle between two planes x+2y+2z=3 and -5x+3y+4z=9 is (A) cos^-1(3sqrt(2))/10 (B) cos^-1 (19sqrt(2))/30 (C) cos^-1 (9sqrt(2))/20 (D) cos^-1 (3sqrt(2))/5

If veca=(3,1) and vecb=(1,2) represent the sides of a parallelogram then the angle theta between the diagonals of the paralelogram is given by (A) theta=cos^-1(1/sqrt(5)) (B) theta=cos^-1(2/sqrt(5)) (C) theta=cos^-1 (1/(2sqrt(5))) (D) theta = pi/2

If the direction cosines of two lines are (1)/(sqrt(6)),(-1)/(sqrt(6)),(2)/(sqrt(6))and(2)/(sqrt(6)),(1)/(sqrt(6)),(-1)/(sqrt(6)) respectively, then the acute angle between them is

If the cosine of the angle between the lines having d.R.s 1,-1,2 and 0,1,a is sqrt(3)/2 , then: a=