Calculating the exponential value in Python

Key takeaways:

  • The exponent value is calculated by multiplying the base number by the number of times specified by the exponent, accommodating positive, negative, and floating-point values.

  • Calculation methods:

    • ** operator: Provides a straightforward way to compute exponentiation (e.g., 2 ** 3)

    • pow() function: A built-in function for computing base raised to an exponent (e.g., pow(base, exponent))

    • math.exp() function: Computes the exponential value of e raised to a power (e.g., math.exp(exponent))

    • numpy.power() function: Useful for element-wise exponentiation in arrays (e.g., numpy.power(base, exponent))

  • Exponentiation is an important mathematical operation for various applications, including data analysis, artificial intelligence, and machine learning.

Exponentiation is a key concept in many programming languages and applications. Whether we are engaged in data analysis, algorithm design, or more specialized fields such as machine learning and artificial intelligence, learning this basic operation is necessary.

Applications of exponentiation

  • Data analysis: Exponentiation helps in analyzing exponential patterns and trends in large datasets.

  • Mathematical calculations: Exponentiation helps in many calculations, such as solving equations, calculating interest rates, etc.

  • Machine learning and AI: Exponentiation is necessary for tasks such as activation functions of neural networks (e.g., exponential linear unit (ELU)) or in image recognition for normalization and feature scaling, which are crucial for training effective models.

What is exponential value?

In Mathematics, the exponential value of a number is equivalent to the number being multiplied by itself a particular set of times. The number to be multiplied by itself is called the base, and the number of times it is to be multiplied is the exponent (the word exponent was first used by Michael Stifel in 1544).

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The exponent and base value can be of different types, as listed below:

  • Positive exponent or base values

  • Negative exponent and base values

  • Floating point exponent and base values

Base

Exponent

Result

Description

2

2

22= 2*2 = 4

Positive base and positive exponent

-2

-3

(-2)-3= 1/(-2)3= -0.125

Negative base and negative exponent

-2

5

(-2)5 = -2*-2*-2*-2*-2 = -32

Negative base and positive exponent

20

-3

(20)-3= 1/(20)3 = 1/(20*20*20) = 0.000125

Positive base and negative exponent

2

1.5

21.5 = 23/2 = (23)1/2= √23 = √8 = 2.828

Positive base and negative floating-point exponent

1.5

2

(1.5)2 = 1.5*1.5 = 2.25

Positive floating-point base and positive exponent

-2.5

3.5

(-2.5)3.5 = (-2.5)7/2 = ((-2.5)7)1/2 = √-(2.5)7 = - 24.7i

Negative floating-point base and positive fractional exponent

In this Answer, we’ll explore five different ways to calculate the exponential value as listed below:

  • Using ** operator

  • Using the Python pow() method

  • Using the math.exp() method

  • Using the math.pow() method

  • Using the numpy.pow() method

How to calculate the exponential value of a number

Python allows users to calculate the exponential value of a number in multiple ways. Let’s look at each of them in detail:

Using the ** operator

The double asterisk, ** operator is a shortcut to calculate the exponential value. Let’s take a look at how this can be used in the following code:

base = 3
exponent = 4
print "Exponential Value is: ", base ** exponent

if we use a negative exponent with a base value of 0, it returns a ZeroDivisionError.

Using the pow() method

In addition to the ** operator, Python has included a built-in pow() function which allows users to calculate the exponential value.

The function takes the base and exponents as input and returns the corresponding value. The general syntax of the function is:

pow(base, exponent)

Look at the coding example to see how it works:

base = 3
exponent = 4
print "Exponential Value is: ", pow(base, exponent)

Using the math.exp() method

The exp() function in Python allows users to calculate the exponential value with the base set to e.

Note:

  1. e is a Mathematical constant known as Euler’s number, with a value approximately equal to 2.71828.
  2. The math library must be imported for this function to be executed.

The function takes the exponent value as the input. The general syntax of the function is:

math.exp(exponent)

Execute the following piece of code to see the result:

import math
exponent = 4
print "Exponential Value is: ", math.exp(exponent)

Using the math.pow() method

The math.pow() function calculates the value of the number raised to the power of another number. The function takes as input the base and exponent and returns the corresponding value. Here is the code example for using the math.pow() method to calculating the exponential value in Python:

import math
base = 3
exponent = 4
print "Exponential Value is: ", math.pow(base, exponent)

Using the numpy.pow() method

Python’s numpy.power() raises the first array elements to the power of the second array elements. Here is the code example for using the math.pow() method to calculate the exponential value in Python:

import numpy as np
arr1 = np.array([2, 3, 4])
arr2 = np.array([4, 2, 3])
print (np.power(arr1, arr2))

Frequently asked questions

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How do we get e in Python?

We can use math.e to get the value of e in Python.


How many digits of e are known?

The known number of digits of e keeps changing, and as of 2010, the known number of computable digits is trillions of digits of e.


How do we write a Python program to display powers of 2?

We can display any number raised to the power of 2 in the following way:

n = int(input("Enter the number: "))
powres = n ** 2
result = f"{n} raised to the power 2 is {powres}."
print(result)

How do we log e in Python?

We can get value of logarithm of e using the math.log(e) function.


What is the difference between math.exp() and math.pow() in Python?

The math.exp() allows users to calculate the exponential value with the base set to e, while math.pow() allows users to calculate the value of the number raised to the power of another number.


Can we compute fractional exponents in Python?

Yes, we can compute fractional exponents in Python. In the following example, we’re using np.power() to calculate fractional exponents:

import numpy as np

arr1 = np.array([9, 25, 16])
arr2 = np.array([1/2, 1/2, 1/2])
print (np.power(arr1, arr2)) 

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