Equation 1

Expand the following: \begin{align} tan(α)= \frac{sin(α)}{cos(α)} =&\cssId{Step1}{tan(α)=\frac{y}{l/2}}\\[3px] &\cssId{Step2}{α=arctan\frac{y*2}{l}}\\[3px] \end{align}

1. Firstly, we use tangent because we have the opposite and the adjacent side of the imaginary trinagle.
2. Secondly, we change the sides to the distances that we know.
3. Finally, you pass the tangent to the other side of the equation so you got all the data to know alpha.