There are a few characters “**constants**” in R and Pi is one of the most used mathematics constants.

**What is Pi in Mathematics**

The pi, which is written as the Greek letter for **p** or **π,** is the ratio of the circumference of any circle to the diameter of that circle.

The circumference of a circle is equal to pi times the diameter (c = πd).

The pi is an irrational number, meaning that its decimal form neither ends (like 1/4 = 0.25) nor becomes repetitive (like 1/6 = 0.166666…).

Pi is an irrational number that’s crucial to many mathematical formulas.

**Pi in R**

Pi is an inbuilt R constant whose value is **3.141593**. The pi constant is a ratio of the circumference of a circle to its diameter. When you define a pi, please note that p of pi is in lowercase.

**Syntax**

`pi`

**Example**

`print(pi)`

**Output**

`[1] 3.141593`

The value of the pi constant in R is 3.141593.

**Calculate the exponential value of pi in R**

To calculate the exponential value of pi in R, use the exp() function.

`[1] 23.14069`

**Output**

`[1] 23.14069`

**Calculate the cos value of pi**

To calculate the cosine value of pi in R, use the cos() function.

`cos(pi)`

**Output**

`[1] -1`

**Find sine value of pi.**

To find the sine value of pi in R, use the sin() function.

`sin(pi)`

**Output**

`[1] 1.224647e-16`

**Find the tangent of pi in R**

To calculate the tangent of pi in R, use the tan() function.

`tan(pi)`

**Output**

`[1] -1.224647e-16`

**Compute the arccos value of pi**

To calculate the arccos value of pi in R, use the acos() function.

`acos(pi)`

**Output**

```
[1] NaN
Warning message:
In acos(pi) : NaNs produced
```

It returns NaN value.

**Compute the arcsin value of pi**

To calculate the arccos value of pi in R, use the asin() function.

`asin(pi)`

**Output**

```
[1] NaN
Warning message:
In asin(pi) : NaNs produced
```

It returns NaN too.

**Compute the arctan value of pi**

To calculate the arccos value of pi in R, use the atan() function.

`atan(pi)`

**Output**

`[1] 1.262627`

**sinpi() in R**

The sinpi() function in R is used to compute the sine value of the input, which is the multiples of pi.

**Syntax**

`sinpi(x)`

**Parameters**

The sinpi() function takes **x **as a numeric value, array, or vector.

**Example**

```
sinpi(0.75)
sinpi(0.5)
sinpi(1)
```

**Output**

```
[1] 0.7071068
[1] 1
[1] 0
```

**Example 2**

```
sinpi(1 / 4)
sinpi(1 / 5)
sinpi(2 / 5)
```

**Output**

```
[1] 0.7071068
[1] 0.5877853
[1] 0.9510565
```

That is it for universal constant pi in R.