Python has *math library* and has many functions regarding to it. One such function is ** expm1()**. This function mathematically computes the value of

`exp(x) - 1`

. This method can be used if we need to compute this very value.

Syntax :math.expm1()

Parameters :

x :Number whose exp(x)-1 has to be computed.

Returns :Returns the computed value of “exp(x)-1”

**Code #1 : ** Demonstrate the working of expm1()

`# Python3 code to demonstrate ` `# the working of expm1() ` `import` `math ` ` ` `# initializing the value ` `test_int ` `=` `4` `test_neg_int ` `=` `-` `3` ` ` `# checking expm1() values ` `# doesn't throw error with negative ` `print` `(` `"The expm1 value using positive integer : "` ` ` `+` `str` `(math.expm1(test_int))) ` ` ` `print` `(` `"The expm1 value using negative integer : "` ` ` `+` `str` `(math.expm1(test_neg_int))) ` |

**Output :**

The expm1 value using positive integer : 53.598150033144236 The expm1 value using negative integer : -0.950212931632136

**“exp() – 1” vs “expm1()”**

There would be a question why `expm1()`

method was even created if we could always compute exp() and then subtract 1 from it. The first reason is that value `exp() - 1`

is used a lot in mathematics and science applications and formulas.

The most important reason is that for smaller value of x, of the order less than e-10, `expm1()`

method give a result more accurate than `exp() - 1`

.

**Code #2 :** Comparing expm1() and exp()-1

`# Python3 code to demonstrate ` `# the application of expm1() ` `import` `math ` ` ` `# initializing the value ` `test_int ` `=` `1e` `-` `10` ` ` `# checking expm1() values ` `# expm1() is more accurate ` `print` `(` `"The value with exp()-1 : "` `+` `str` `(math.exp(test_int)` `-` `1` `)) ` `print` `(` `"The value with expm1() : "` `+` `str` `(math.expm1(test_int))) ` |

**Output :**

The value with exp()-1 : 1.000000082740371e-10 The value with expm1() : 1.00000000005e-10

## leave a comment

## 0 Comments