math.log is the natural logarithm:
From the documentation:
math.log(x[, base]) With one argument, return the natural logarithm of x (to base e).
Your equation is therefore:
n = math.log((1 + (FV * r) / p) / math.log(1 + r)))
Note that in your code you convert n to a str twice which is unnecessary
Top answer 1 of 2
93
math.log is the natural logarithm:
From the documentation:
math.log(x[, base]) With one argument, return the natural logarithm of x (to base e).
Your equation is therefore:
n = math.log((1 + (FV * r) / p) / math.log(1 + r)))
Note that in your code you convert n to a str twice which is unnecessary
2 of 2
12
Here is the correct implementation using numpy (np.log() is the natural logarithm)
import numpy as np
p = 100
r = 0.06 / 12
FV = 4000
n = np.log(1 + FV * r/ p) / np.log(1 + r)
print ("Number of periods = " + str(n))
Output:
Number of periods = 36.55539635919235
Python
docs.python.org › 3 › library › math.html
math — Mathematical functions
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W3Schools
w3schools.com › python › ref_math_log.asp
Python math.log() Method
The math.log() method returns the natural logarithm of a number, or the logarithm of number to base. ... If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail: sales@w3schools.com · If you ...
Scaler
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How to Calculate ln in Python? - Scaler Topics
October 10, 2025 - The Math.log() method of math library can be used to calculate ln in Python.
Vultr Docs
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Python Numpy log() - Calculate Natural Logarithm | Vultr Docs
November 15, 2024 - Click below to sign up and get $250 of credit to try our products over 30 days · The log() function from the Numpy library in Python is a versatile tool for computing the natural logarithm of an array of numbers, where the natural logarithm ...
GeeksforGeeks
geeksforgeeks.org › python › log-functions-python
Log functions in Python - GeeksforGeeks
August 14, 2024 - Syntax : math.log(a,Base) Parameters : a : The numeric value Base : Base to which the logarithm has to be computed. Return Value : Returns natural log if 1 argument is passed and log with specified base if 2 arguments are passed. Exceptions : Raises ValueError if a negative no. is passed as argument. ... # Python code to demonstrate the working of # log(a,Base) import math # Printing the log base e of 14 print ("Natural logarithm of 14 is : ", end="") print (math.log(14)) # Printing the log base 5 of 14 print ("Logarithm base 5 of 14 is : ", end="") print (math.log(14,5))
DigitalOcean
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Python log() Functions to Calculate Logarithm | DigitalOcean
August 4, 2022 - The math.log(x,Base) function calculates the logarithmic value of x i.e.
Centron
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Python log() Function to Calculate Logarithm
February 7, 2025 - Python provides several variants of the log() function to calculate logarithms to specific bases or in unique scenarios: ... The math.log2(x) function computes the logarithm of x to the base 2, commonly used in computer science.
datagy
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Python Natural Log: Calculate ln in Python • datagy
December 30, 2022 - Learn how to use Python to calculate the natural log (logarithm), known as ln, using the math and numpy libraries, and how to plot it.
NumPy
numpy.org › doc › 2.1 › reference › generated › numpy.log.html
numpy.log — NumPy v2.1 Manual
M. Abramowitz and I.A. Stegun, “Handbook of Mathematical Functions”, 10th printing, 1964, pp.
Note.nkmk.me
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Power and Logarithmic Functions in Python: exp, log, log10, log2 | note.nkmk.me
August 10, 2023 - If the second argument is omitted, ... a base of e and is represented in mathematics by "log" or "ln", can be calculated using math.log(x)....
Python Forum
python-forum.io › thread-2599.html
Natural Logarithm in Python
OHello all, I'm relatively new at Python; I need to input an equation, but I need help with expressing the Natural Logarithm in Python (ln): The equation is: (7.35 x E) + [17.34 x ln(Len)] + [4.96 x ln(Conc)] + [0.89 x ln(DNA)] - 25.42 E, Len, ...
NumPy
numpy.org › devdocs › reference › generated › numpy.log.html
numpy.log — NumPy v2.5.dev0 Manual
M. Abramowitz and I.A. Stegun, “Handbook of Mathematical Functions”, 10th printing, 1964, pp.
KooR.fr
koor.fr › Python › API › python › math › log.wp
KooR.fr - Fonction log - module math - Description de quelques librairies Python
Par exemple, ln(e²) == 2. pour information, math.log(x, base) == math.log(x)/math.log(base).
GeeksforGeeks
geeksforgeeks.org › python › numpy-log-python
numpy.log() in Python - GeeksforGeeks
January 13, 2026 - Python numpy-Mathematical Function · Python Fundamentals · Python Introduction2 min read · Input and Output in Python4 min read · Python Variables4 min read · Python Operators4 min read · Python Keywords2 min read · Python Data Types8 min read · Conditional Statements in Python3 min read ·
Pythonforundergradengineers
pythonforundergradengineers.com › exponents-and-logs-with-python.html
Exponents and Logs with Python - Python for Undergraduate Engineers
June 27, 2022 - The following exponent and logarithm functions can be imported from Python's math module: ... Note that Python's log function calculates the natural log of a number. Python's log10 function calculates the base-10 log of a number. Python doesn't have an ln function, use log for natural logarithms.
Top answer 1 of 6
275
np.log is ln, whereas np.log10 is your standard base 10 log.
2 of 6
25
Correct, np.log(x) is the Natural Log (base e log) of x.
For other bases, remember this law of logs: log-b(x) = log-k(x) / log-k(b) where log-b is the log in some arbitrary base b, and log-k is the log in base k, e.g.
here k = e
l = np.log(x) / np.log(100)
and l is the log-base-100 of x
Codecademy
codecademy.com › docs › python:numpy › math methods › .log()
Python:NumPy | Math Methods | .log() | Codecademy
July 15, 2024 - Calculates the natural logarithm of each element in an array.
NumPy
numpy.org › doc › stable › reference › generated › numpy.log.html
numpy.log — NumPy v2.4 Manual
M. Abramowitz and I.A. Stegun, “Handbook of Mathematical Functions”, 10th printing, 1964, pp.
Enterprise DNA
blog.enterprisedna.co › python-natural-log
Python Natural Log: Quick Guide for Calculations – Master Data Skills + AI
The natural logarithm (often abbreviated as “ln”) in Python is a mathematical function that calculates the logarithm of a number to the base ‘e’, where ‘e’ is Euler’s number, approximately equal to 2.71828. It’s widely used in many areas of science and engineering.