Direction Cosines

Angle any vector $\vec{v}=[a,b,c]$ makes with any direction vector($\vec{i},\vec{j},\vec{k}$) Angle $\alpha$ is from $\vec{i}$ to $\vec{v}$ $\cos \alpha =\frac{\vec{v}\cdot \vec{i}}{|\vec{v}|}=\frac{a}{|\vec{v}|}$ $\cos \beta =\frac{\vec{v}\cdot \vec{j}}{|\vec{v}|}=\frac{b}{|\vec{v}|}$ $\cos \gamma =\frac{\vec{v}\cdot \vec{k}}{|\vec{v}|}=\frac{c}{|\vec{v}|}$