The line of greatest slope on an inclined plane `P_1` is that line in the plane which is perpendicular to the line of intersection of plane `P_1` and a horiontal plane `P_2`.
Q. Assuming the plane `4x-3y+7z=0` to be horizontal, the direction cosines of line greatest slope in the plane `2x+y-5z=0` are

Options

A. a. `(x)/(3)=(y)/(1)=(z)/(-1)`
B. b. `(x)/(3)=(y)/(-1)=(z)/(1)`
C. c. `(x)/(-3)=(y)/(1)=(z)/(1)`
D. d. `(x)/(1)=(y)/(3)=(z)/(-1)`

Answer

(b)