" If a line makes angles "alpha,8,y" with the co-ordinate axes then "cos2 alpha+cos28+cos2y-

If a line makes angles alpha ,beta , gamma with the co-ordinates axes, then cos 2alpha +cos 2beta +cos 2gamma is :

If a line makes angles alpha,beta,gamma with co-ordinate axes, then cos2alpha+cos 2 beta+cos2gamma=

If a line makes angles alpha,beta,gamma with co-ordinate axes, then cos2alpha+cos 2 beta+cos2gamma= a) -2 b) -1 c) 1 d) 2

If a line makes angles alpha, beta, gamma with the coordinate axes, prove that cos2alpha + cos 2beta + cos2gamma + 1 = 0 .

If a line makes angles alpha,beta and gamma with the coordinate axes,then prove that cos2 alpha+cos2 beta+cos2 gamma=-1

If a line in the space makes angle alpha,beta and gamma with the coordinate axes, then cos2alpha+cos2beta+cos2gamma+sin^2alpha+sin^2beta+sin^2gamma equals