1. find the exact value of the expression cos [tan^-1(sqrt3/3)]

2. An astrouant observe the cities that are 48km apart, the angle between the lines of sight is 7.6 degree. Given that he is the same distance from each, how high above the surface of the earth is he? Ignore the earths curvature.

3. Find the measure of the least positive angle that is coterminal with the angle given. Then find the meassure of the negative angle that is nearest to and is coterminal with the angle given -146 degree.

4. Convert the angle D^o M^' s^"

5. find 0 or < theta or <2pi