Posted by Grace on .
If α, β, and γ are direction angles for a vector in three dimensions and cos α = 0.6 and cos β = 0.7, find cos γ

Precalc 
Steve,
recall that
cos^{2}α + cos^{2}β + cos^{2}γ = 1
.36 + .49 + cos^{2}γ = 1
cos^{2}γ = .15
cosγ = 0.38