Cosine is a trigonometric operator. It is related to the angles created by a right-angle triangle. * Excel* offers a dedicated function named

*to evaluate the cosine value of an angle. But it does not take the angle in degree units but in radian units. In this article we will show how to use*

**the COS function***with degrees.*

**Excel COS function**## Download Practice Workbook

You can download the practice book here.

## Overview of Excel COS Function

**Summary**

* The COS function* in

*returns the value of the cosine operator of a particular angle. The angle that is delivered as the only function argument should be in radians.*

**Excel****Generic Syntax**

**COS (number)**

**Argument Description**

ARGUMENT | REQUIRMENT | EXPLANATION |
---|---|---|

number |
Required | This the angle in radian units for which we will get the cosine value. |

## 2 Easy Ways to Use Excel COS Function with Degrees

In this article, we will discuss two ways to convert degrees to radians and use them in * the Excel COS function*. Firstly, we will use the RADIANS function to directly convert the degrees into radian units. Then, we will use

*to transform degrees into radians.*

**the PI function**### 1. Using RADIANS Function

* The RADIANS function* takes degrees as its units and then turns them into radian units. In this method, we will use it to convert degrees into radians and deliver them as the arguments of

*.*

**the COS function****Steps:**

- Firstly, select the
cell and write down the following formula,**C5**

`=COS(RADIANS(B5))`

- Then, hit
.**Enter**

- Consequently, we will get the cosine value of the particular angel.
- Finally, move the cursor down to the last data cell and
will automatically fill the cells according to the formula.**Excel**

**Note:**

- As we can see in the
cell the value of**C10**degrees is not zero. But in practice, we know that it will be zero. This is because of the conversion mechanism of decimal numbers by**cos 90**.**Excel**

- To avoid it, write the following formula in the
cell,**C10**

`=ROUND(COS(RADIANS(B10)),12)`

- Then, hit
.**Enter**

- As a result,
will automatically round the result to zero.**Excel**

ðŸ”Ž **Formula Breakdown:**

**RADIANS(B10):**This will turn the degrees in thecell into radians.**B10****COS(RADIANS(B10)):**This will return the cosine value for the radian angle supplied by. This value will be very close to zero,**the RADIAN function****6.12574 E-17.****ROUND(COS(RADIANS(B10)),12):**will round the value up to**The ROUND function**numbers and eventually return zero.**12**

**Read More: Why Cos 90 Is Not Equal to Zero in Excel?**

### 2. Applying PI Function

* The PI function* returns the value of pi, a constant number, up to

*digits after the decimal point. In this instance, we will convert the degrees into radians using*

**15***.*

**the PI function**The formula to change the degree from radian will be,

**Radian = ( Degree * Pi/180)**; Here, **Pi= 3.14159265358979**

**Steps:**

- To begin with, select the
cell and write down the following formula,**C5**

`=COS(B5*PI()/180)`

- After that, hit
.**Enter**

- As a result, the cosine value of the particular angel will be in the
cell.**C5** - Finally, lower the cursor down to the last data cell to get the values for the rest of the angles.

## How to Calculate Inverse Cosine in Excel

The inverse cosine of a number indicates the radian angle of a particular cosine value. * Excel *offers

*to calculate the inverse cosine value.*

**the ACOS function***takes numbers as its input and returns radian values.*

**The ACOS function****Steps:**

- To start with, select the
cell and write down the following formula,**C5**

`=ACOS(B5)`

- After that, hit the
button.*Enter*

- As a result, the inverse cosine value will be in the
cell.**C5** - Finally, lower the cursor down to the last data cell to get the values for the rest of the angles.

**Note:**

In the following image, we can see that * the ACOS function* is returning an error for the

*and*

**1.5***values. This happens because*

**-2***returns a valid output only for numbers that fall in the range*

**the ACOS function***to*

**-1***.*

**1****Read More: Excel COS Function Is Returning Wrong Output?**

## Conclusion

In this article, we have discussed * 2* ways to use

*with degrees. This will help users to calculate the cosine value of an angle expressed in degrees.*

**the Excel COS Function**