In a function such as sine or cosine, we could also have a translation of the form: \(y = \sin (x - a)^\circ\) where \(a\) is called the phase angle. This is when the graph of the function has ...

but many fail to make the leap on how crucial circles are for trig functions. With static graphs and equations, it's possible to get a handle on the rules of what various functions do and mean.