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 the co-ordinates axes, then cos 2alpha +cos 2beta +cos 2gamma is :

If a line makes angles alpha, beta, gamma with the axes then cos2alpha +cos2beta+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, gamma with the axes then cos2alpha +cos2eta+cos2gamma = (A) -2 (B) -1 (C) 1 (D) 2

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

If a line in the space makes angles alpha, beta, " and " gamma with the coordinatess axes, then cos2alpha+cos2beta+cos2gamma+sin^(2)alpha+sin^(2)beta+sin^(2)gamma=

If a line makes angle alpha,beta,gamma with the axes respectively, then cos 2alpha+cos 2beta + cos 2gamma =