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.

Returns: 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:

• Example 1:
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  <script>    // Different numbers are being taken // as the parameter of the function. document.write(Math.log1p(1000) + "<br>"); document.write(Math.log1p(12) + "<br>"); document.write(Math.log1p(26) + "<br>"); document.write(Math.log1p(5));    </script>

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  Output:

  6.90875477931522
  2.5649493574615367
  3.295836866004329
  1.791759469228055

• Example 2:
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  <script>    // Taken parameter from 1 to 19 incremented by 3. for (i = 1; i < 20; i += 3) {     document.write(Math.log1p(i) + "<br>"); }    </script>

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  Output:

  0.6931471805599453
  1.6094379124341003
  2.0794415416798357
  2.3978952727983707
  2.639057329615259
  2.833213344056216
  2.995732273553991
  

Errors and exceptions: 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.

• Example 1:
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  <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>

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  Output:

   NaN
  

• Example 2: This function gives error when its parameter is taken as complex number because it accepts only integer value as the parameter.
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  <script>        // Parameters can never be a complex number because     // it accept only integer value as the parameter.     document.write(Math.log1p(1 + 2i));    </script>

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  Output:

  Error: Invalid or unexpected token
  

• Example 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.
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  <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>

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  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:

• Example 1:
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  <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>

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  Output:

  1.146128035678238

Supported Browsers: The browsers supported by JavaScript Math.log1p( ) function are listed below:

• Google Chrome
• Internet Explorer
• Firefox
• Opera
• Safari

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