JavaScript | Math.log1p()

The Math.log1p() is an inbuilt function in JavaScript which gives the value of natural logarithm of 1 + p number. Natural logarithm is of base e, where e is an irrational and transcendental number approximately equal to 2.718.
Syntax:

Math.log1p(1 + p)

Parameters:

In parameter 1+p, p is any number whose natural logarithm of base e is being calculated.

Return Values:

It returns the value of base e of logarithm of any number added with 1.

Examples:

Input:
Math.log1p(5)

Output:
1.791759469228055

Explanation:
Here value of natural logarithm of number 5 is 1.791759469228055 as shown output.

Input:
Math.log1p(10)

Output:
2.3978952727983707

Let’s see some JavaScript code on this function:
Code #1:

Output:

6.90875477931522
2.5649493574615367
3.295836866004329
1.791759469228055

Code #2:

Output:

0.6931471805599453
1.6094379124341003
2.0794415416798357
2.3978952727983707
2.639057329615259
2.833213344056216
2.995732273553991

Errors and exceptions:
1. Parameters for this function should always be a number otherwise it returns NaN i.e, not a number when its parameter is taken as a string.

   <script>        // Parameters for this function should always be a     // number otherwise it return NaN i.e, not a number     // when its parameter taken as string.     document.write(Math.log1p("gfg"));    </script>

   Output:

    NaN
   

2. This function gives error when its parameter is taken as complex number because it accepts only integer value as the parameter.

   <script>        // Parameters can never be a complex number because     // it accept only integer value as the parameter.     document.write(Math.log1p(1 + 2i));    </script>

   Output:

   Error: Invalid or unexpected token
   

3. This function returns NaN i.e, not a number if the parameter is less than -1 because number should be any positive number i.e, greater then 0.

   <script>        // This function return NaN i.e, not a number     // if the parameter is less     // than -1 because number should be     // any positive number i.e, greater then 0.     document.write(Math.log1p(-2));    </script>

   Output:

    NaN
   

Application:

• Whenever we need to find the value of natural logarithm of 1 + p number that time we take the help of this function. Its value needed many times in mathematics problem.
  Let’s see JavaScript code for this application:
  Code #1:

  <script>        // taking parameter as number 14 and calculated     // in the form of function.     function value_of_base_e_logarithms_of_any_number() {         return Math.log10(14);     } document.write(value_of_base_e_logarithms_of_any_number());    </script>

  Output:

  1.146128035678238