If  α,β,γ are the angles which a line makes with the positive direction of coordinate axes, then the value of cos2α−sin2β+cos2γ=

If α,β,γ, are the angles made by a line ‘L’ with the coordinate axes in the positive direction then cos2α+cos2β+cos2γ=1It implies that cos2α+1−sin2β+cos2γ=1⇒cos2α−sin2β+cos2γ=0