" 10.If "a+beta=7." prove that "cos^(2)a+cos^(2)beta+cos^(2)gamma=1+2cos a 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. then cos^(2)alpha+cos^(2)beta+cos^(2)gamma-2 cos alpha cos beta cos gamma=

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

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

If alpha+beta=gamma ,show that cos^2alpha+cos^2beta+cos^2gamma=1+2cosalphacosbetacosgamma

if alpha+beta+gamma=2pi prove that cos^2alpha+cos^2beta+cos^2gamma-2cosalphacosbetacosgamma=1

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

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