设与三个坐标轴的夹角为：a、b、c,因3个角相等,故：cosa=cosb=cosc而：cosa^2+cosb^2+cosc^2=1,故：cosa^2=1/3,即：cosa=sqrt(3)/3或-sqrt(3)/3即方向余弦：cosa=cosb=cosc=sqrt(3)/3或cosa=cosb=cosc=-sqrt(3)/3...
