Question

What is the reference angle for cos 2pie/3

Answer 1

Answer:

Step-by-step explanation:

If your mind works better in degrees than it does radians, as does mine, it will be beneficial to us to see what degree measure this angle is. Convert it to degrees using the fact that 180° = π:

$\frac{2\pi}{3}*\frac{180}{\pi}=120$ degrees

Now that we know that, we can plot that angle in a coordinate plane. The terminal side of the angle lands in quadrant 2. To find the reference angle, we subtract 120 from 180 and get that the reference angle is 60 degrees, which is the same as π/3.