How to Find Exponential in JavaScript

The exp() is the static method of Math; therefore, it is always used as Math.exp() rather than as a method of the Math object created.

JavaScript exponential

To find an exponential value in JavaScript, use the Math.exp() method. JavaScript Math.exp() function is used to return ex, where x is an argument, and e is the Euler’s number, which is a base of the natural logarithms. 

Syntax

Math.exp(x)

Parameter(s)

The variable x, whose exponential value is ex, must be determined.

Return Value

The exponential value ex.

See the following method.

JavaScript Math.exp()

Note

  1. For a positive argument x, Math.log(Math.exp(x)) gives the value x.
  2. If the argument is negative infinity, then this method returns 0.
  3. If the argument is positive infinity, then this method returns positive infinity.
  4. If an argument is positive zero or negative zero, then this method returns 1.
  5. If the passed value is not a valid number, the method returns NaN.
  6. If the passed value is null, the method returns 1.

Compatibility(Version and above)

  1. Google Chrome v1
  2. Internet Explorer v3
  3. Firefox v1
  4. Edge v12
  5. Opera  
  6. Safari v1
  7. Android webview v1 
  8. Chrome for Android v18
  9. Firefox for Android v4
  10. Opera for Android 
  11. Safari on iOS v1
  12. Samsung Internet v1.0
  13. Node.js

JavaScript version: ECMAScript 1

JavaScript exp()

The following code demonstrates the use of the Javascript exp() method.

// example1.js

var a = 1;
var b = -1;
var c = 2;
var d = 3;

console.log(Math.exp(a));
console.log(Math.exp(b));
console.log(Math.exp(c));
console.log(Math.exp(d));

Output

node example1
2.718281828459045
0.36787944117144233
7.38905609893065
20.085536923187668

Example 2

The following example demonstrates that if the passed value is not a valid number, then the method returns NaN.

// example2.js

var a = "JavaScript";
var b;

console.log(Math.exp(a));
console.log(Math.exp(b));

Output

node example2
NaN
NaN

Example 3

JavaScript exp() method cannot be used with complex arguments, as only integer arguments are accepted.

// example3.js

//Complex values cannot be passed as arguments as follows
//since only integer arguments are accepted.

console.log(Math.exp(2+i));

Output

node example3
ReferenceError: i is not defined

Example 4

The following example demonstrates that for a positive x: ln(ex) = x.

// example4.js

var x = 10;
var a = Math.exp(x);

console.log(Math.log(a));

Output

node example4
10

Example 5

The following example demonstrates the case of the parameter as infinity(positive/negative) and zero(positive/negative).

See the following code.

//example5.js

var a = Number.POSITIVE_INFINITY;
var b = Number.NEGATIVE_INFINITY;

var c = 0;
var d = -0;

console.log(Math.exp(a));
console.log(Math.exp(b));
console.log(Math.exp(c));
console.log(Math.exp(d));

Output

node example5
Infinity
0
1
1

Example 6

The following example demonstrates that if null is passed as an ent, this method returns 1.

// example6.js

var a = null;
var b = "";
var c = [];

console.log(Math.exp(a));
console.log(Math.exp(b));
console.log(Math.exp(c));

Output

node example6
1
1
1

Example 7

The following example demonstrates the application of this method in a simple programming context.

Given any x, compute the value of the infinite series:

1 + x/1! + x2/2! + x3/3! + x4/4! + … 

[Now, it would be tough to devise a program to solve this. But since

1 + x/1! + x2/2! + x3/3! + x4/4! + …  = ex,

It can be done within a few lines of code]

See the following code.

// example7.js

var x;

const r = require('readline');
const rl = r.createInterface({
  input: process.stdin,
  output: process.stdout
});

const prompt1 = () => {
  return new Promise((resolve, reject) => {
    rl.question('x: ', (answer) => {
      x = answer;
      resolve();
    });
  });
};

const main = async () => {
  await prompt1();
  rl.close();
  console.log();
  console.log('The value of the series 1 + x/1! + (x^2)/2! + (x^3)/3! + ... :');
  console.log(Math.exp(x));
}
main();

Output

node example7
Test Case 1:
x: 1

The value of the series 1 + x/1! + (x^2)/2! + (x^3)/3! + ... :
2.718281828459045

Test Case 2:
x: 2

The value of the series 1 + x/1! + (x^2)/2! + (x^3)/3! + ... :
7.38905609893065

That’s it.

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