Question

Find the exact value of arccos -(sqrt(3)/(2)) without using a calculator.

Answer 1

look at cheat sheet here
http://tutorial.math.lamar.edu/cheat_table.aspx

Answer 2

find the angle (number) whose cosine is \[-\frac{\sqrt{3}}{2}\] in other words look at the unit circle on the bottom and find the angle where that is the first coordinate

Answer 3

make sure you are looking at the upper half of the circle between 0 and pi or between 0 and 180 if you are working in degrees

Answer 4

so I got 5pi/3 but does the arc part mean anything???

Answer 5

arc just means ur going in reverse to figure out x in cos(x) = given value.
The trig value u have is a special angle.