Refer to the reference angles section below for more detail as well as a table of the signs of the six trigonometric functions in each quadrant.
We can find the values of the other trigonometric functions in the same way. Similarly, since the value for cos(330°) in quadrant IV is positive, it has the same value as cos(30°).
Since the values of cosine in quadrants II and III are negative, the value for cosine for the corresponding angles in quadrants II and III (150° and 210°) is. For example, the value of cosine for 30° or in the first quadrant is. Although the table does not include the multiples of each angle in each quadrant, we can use the table to find the values of the other angles the values are the same for each corresponding angle, taking the sign of the respective quadrant into consideration.
