On scientific calculators, the inverse trigonometric functions such as `cos^-1,` `sin^-1` , and `tan^-1` are displayed at the top of the buttons cos, sin and tan, respectively. To be able to use these functions, 2nd key should be pressed. On some scientific calculators, the 2nd key is labelled as SHIFT key.

Moreover, when using the inverse trigonometric functions, the result displayed can either be in degrees or in radians. For the result to be displayed in degrees, set the mode of the calculator to degrees before performing the calculations. Otherwise, set the mode to radians.

Consider these examples.

Example 1: Find the `sin^-1(0.5)` in degrees using scientific calculator.

For this problem, it wants the result to be in degrees. So, set the mode of the scientific calculator to degrees.

Then, press the buttons **2nd** and** sin**. Then, input 0.5 and press **ENTER**.

The result displayed will be 30. This means that it is 30 degrees.

**Therefore, `sin^-1(0.5)=30^o` .**

Example 2: Find the `cos^(-1)(-1)` in degrees using scientific calculator.

Set the mode of the calculator to degrees.

Then, press **2nd** and **cos** buttons. Then, type -1 and press **ENTER**.

The result will be 180. The unit of this is degrees.

**Thus, `cos^(-1) (-1)=180^o` .**

Example 3: Find the `tan^(-1)(1)` in degrees using scientific calculator.

Set the mode of the calculator to degrees.

Then, press **2nd** and **tan** keys. Then, input 1 and press **ENTER**.

The result will be 45. Its unit is degrees.

**Hence, `tan^-1(1)=45^o` .**