Let's turn to the functions and see how they work with this inverse key.
Notice that the numerator and denominator of the cosecant, **H/O**, are the reverse of the sine, **O/H**. They have an inverse relationship. In fact, all the functions on the right are inverse to the functions on the left, and vice versa.

For example: With the 3-4-5 right triangle, the Sin = 3/5 and the Csc = 5/3. **3/5 = 0.6 and 5/3 = 1.67**

This chart shows these inverse relationships.

To determine a function using the inverse key:

**First:** Determine the function which is inverse to the function you want.
**Second:** Do your calculations based on that function.
**Third:** Push the inverse key **1/x**.

For example, to find the cosecant of an angle:

**For example:** The cosecant of 24° is found in this manner.

The cosecant of 24° is **2.4589**.

**Using the Inverse Key with Functions: Practice**

Find the indicated function for each angle below. Round off to 4 decimal places.

**Remember:** Use the calculator key that is the inverse of these functions **first**, then the **1/x** key.

(1) csc 40° (5) cot 60°
(2) sec 45° (6) csc 24°
(3) cot 34° (7) sec 65°
(4) sec 12° (8) cot 1°