If `alpha + beta = gamma` prove that `cos^2 alpha+ cos^2 beta+cos^2gamma=1+2cos alpha cos beta cos gamma`

If alpha+beta=gamma prove that cos^(2)alpha+cos^(2)beta+cos^(2)gamma=1+2cos alpha cos beta cos gamma

If alpha+beta+gamma=2pi , prove that : cos^2 alpha + cos^2 beta + cos^2 gamma-2cosalpha cosbeta cosgamma=1 .

If cos alpha+cos beta+cos gamma=0; then prove that cos3 alpha+cos3 beta+cos3 gamma=12cos alpha cos beta cos gamma

If cos alpha+cos beta+cos gamma=0, then prove that cos3 alpha+cos3 beta+cos3 gamma=12cos alpha cos beta cos gamma

if cos alpha+cos beta+cos gamma=0=sin alpha+sin beta+sin gamma then prove that cos2 alpha+cos2 beta+cos2 gamma=sin2 alpha+sin2 beta+sin2 gamma=0

cos^(2) alpha +cos^(2) beta +cos^(2) gamma is equal to

If cos alpha + cos beta + cos gamma = 3 then sin alpha + sin beta + sin gamma =

If cos alpha + cos beta + cos gamma = 0 then cos 3alpha + cos 3beta + cos 3gamma = lambda cos alpha *cos beta*cos gamma where lambda is equal to

If alpha, beta , gamma are direction-angles of a line, prove that (i) cos2alpha + cos 2 beta +cos2 gamma+ 1 = 0 . (ii) cos 2 alpha + cos 2 beta + cos 2 gamma = -1 .