Angle Between a Vector and a Coordinate Axis
If:
$$\vec a=a_x\hat i+a_y\hat j+a_z\hat k$$
then the angle $$\alpha$$ with the x-axis satisfies:
$$\cos\alpha=\frac{a_x}{|\vec a|}$$
Similarly:
$$\cos\beta=\frac{a_y}{|\vec a|}$$
$$\cos\gamma=\frac{a_z}{|\vec a|}$$
Usage
- Used to determine direction angles from vector components.