Q:

How to find the degrees between 2 vectors when I have $\arccos$ just in radian mode?

I'm trying to write in java a function which finds the angles, in degrees, between 2 vectors, according to the follow equation  - 
$$\cos{\theta} = \frac{\vec{u} \cdot \vec{v}}{\|\mathbf{u}\|\|\mathbf{v}\|}$$ 
but in java the Math.acos method returns the angle radians, so what I have to do after I calculate $\frac{\vec{u} \cdot \vec{v}}{\|\mathbf{u}\|\|\mathbf{v}\|}$, to get it in degrees? 

A:

You can compute the angle, in degrees, by computing the angle in radians, and then multiplying by 
$\dfrac {360}{2\pi} = \dfrac {180\; \text{degrees}}{\pi\; \text{radians}}$:
$$\theta = \arccos\left(\frac{\vec{u} \cdot \vec{v}}{\|\mathbf{u}\|\|\mathbf{v}\|}\right)\cdot \frac {180}{\pi}$$

A:

After calculating the value in radians, simply multiply by $\frac {180}{\pi}$ to convert it into degrees.

