## What is the ACOS function in Excel?

The **ACOS **function is one of the math functions of Excel.

It returns the arccosine of a number, in radians in the range 0 to Pi.

The arccosine is the angle whose cosine is the Number.

The domain of arccosine is the interval [−1,1] and it’s undefined elsewhere.

We can find this function in **Math&trig** of insert function Tab.

## How to use ACOS** **function in excel

- Click on an empty cell (like F5).

2. Click on the **fx **icon (or press** shift+F3**).

3. In the insert function tab you will see all functions.

4. Select **math and trig** category.

5. Select **ACOS **function.

6. Then select **ok**.

7. In the function arguments Tab you will see ** ACOS **function.

8. Number field is the cosine of the angle you want and must be from -1 to +1.

9. You will see the result in the formula result section ( ** ACOS** (1)=0).

## Examples of **ACOS** function in excel

**Example 1:**

**How to use ACOS function in excel**

You can see examples of ACOS function below:

**acos**(-1) ----->>>>answer is 3.141
**acos**(-0.5) ----->>>>answer is 2.094
**acos**(0) ----->>>>answer is 1.570
**acos**(0.5) ----->>>>answer is 1.047
**acos**(1) ----->>>>answer is 0

math.acos(a).

### How to plot Y=ACOS(X) with python code in excel

we can use Python code for acos function in excel:

```
import math
import numpy as np
import matplotlib.pyplot as plt
x =np.linspace(–1,+1, 100)
lenx=len(x)
y=[]
for i in range(lenx):
y.append(math.acos(x[i]))
i +=1
plt.plot(x,y)
plt.show()
```

## What is the purpose of **ACOS** function?

It returns the arccosine of a number, in radians in the range 0 to Pi. The arccosine is the angle whose cosine is the Number.

## What is the Return value of **ACOS** function?

It returns a number.

## How many arguments does **ACOS** function have?

This function has just **1** Argument.

The **argument **of ACOS function is **number**.

Number field is the cosine of the angle you want and must be from -1 to +1.

The argument of ACOS function is **required **and not optional.

```
ACOS(number) = number
```

## Which version of excel supports **ACOS** function?

This function is available for all excel **versions **(2003-2019).