91Ó°ÊÓ

For the following exercises, use reference angles to evaluate the expression. $$ \tan \frac{5 \pi}{6} $$

For the following exercises, use reference angles to evaluate the expression. $$ \sec \frac{7 \pi}{6} $$

For the following exercises, use reference angles to evaluate the expression. $$ \tan \frac{8 \pi}{3} $$

For the following exercises, use reference angles to evaluate the expression. $$ \sec 120^{\circ} $$

When a right triangle with a hypotenuse of 1 is placed in the unit circle, which sides of the triangle correspond to the \(x-\) and \(y\) -coordinates?

For the following exercises, find the lengths of the missing sides if side \(a\) is opposite angle \(A,\) side \(b\) is opposite angle \(B,\) and side \(c\) is the hypotenuse. $$ \cos B=\frac{4}{5}, a=10 $$

A radio tower is located 400 feet from a building. From a window in the building, a person determines that the angle of elevation to the top of the tower is \(36^{\circ},\) and that the angle of depression to the bottom of the tower is \(23^{\circ} .\) How tall is the tower?

There is lightning rod on the top of a building. From a location 500 feet from the base of the building, the angle of elevation to the top of the building is measured to be \(36^{\circ} .\) From the same location, the angle of elevation to the top of the lightning rod is measured to be \(38^{\circ} .\) Find the height of the lighthning rod.

The angle of elevation to the top of a building in New York is found to be 9 degrees from the ground at a distance of 1 mile from the base of the building. Using this information, find the height of the building.

For the following exercises, use reference angles to evaluate the given expression. $$ \sec \frac{11 \pi}{3} $$