Show that cot (-390°)-4 cos 480 = 2-sqrt3.?
1 Answer
Mar 27, 2018
See the method below.
Explanation:
Recall that
Since all trigonometric functions repeat after 360˚ we can add or subtract 360˚ to the angles without changing anything. Doing this we get
We can write
This can be further simplified as
Consulting the unit circle we find the following:
We can now substitute these values in.
Simplifying we get
Rearranging we get