=4/sqrt(16+9+25)=4/sqrt(50)=4/(5sqrt(2))=(2sqrt(2))/5,
cos β =y/sqrt(x^(2)+y^(2)+z^(2))=3/sqrt(4^(2)+3^(2)+5^(2))=
=3/sqrt(16+9+25)=3/sqrt(50)=3/(5sqrt(2))=(3sqrt(2))/10,
cos γ =z/sqrt(x^(2)+y^(2)+z^(2))=5/sqrt(4^(2)+3^(2)+5^(2))=
=5/sqrt(16+9+25)=5/sqrt(50)=5/(5sqrt(2))=(sqrt(2))/2.