Question

How do you find reference angles?

Answer 1

On the unit circle. For instance, what is the reference angle of (theta) = 2pi/3?

Answer 2

Since \(\dfrac\pi2 <\dfrac{2\pi}3<\pi\), we have \(\pi-\dfrac{2\pi}3= \boxed{\dfrac\pi3}\)

Answer 3

If your angle \(\theta\) is in Q2: \(\large\rm ref=\pi-\theta\)
If your angle \(\theta\) is in Q3: \(\large\rm ref=\theta-\pi\)
If your angle \(\theta\) is in Q4: \(\large\rm ref=2\pi-\theta\)

This might be helpful to remember :)