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The antilog of a number is the inverse of its logarithm, and can be calculated in Python using the built-in math module. The math.exp() function can be used to calculate the antilog of a value, by passing in the logarithm of the value as an argument. The antilog of a number is also sometimes referred to as its exponentiation. For example, the antilog of 10 is the same as calculating 10 to the power of the log value, which is equal to 10,000. In Python, this could be calculated with math.exp(4).
The antilog of a number is the inverse of the log of a number.
So, if you calculate the log of a number you can then use the antilog to get back the original number.
For example, suppose we start with the number 7. If we take the log (base 10) of 7 then we would get .845:
log10(7) = .845
The antilog (base 10) of the value 0.845 can be found by taking 10 raised to the power of 0.845:
10.845 = 7
The antilog allowed us to get back the original number.
The following table shows how to calculate the antilog of values in Python according to their base:
| Base | Number | Log | Antilog |
|---|---|---|---|
| e | x | np.log(x) | np.exp(x) |
| 10 | x | np.log10(x) | 10 ** x |
The following examples show how to calculate the antilog of values in Python using different values for the base.
Example 1: Calculating the Antilog of Base 10
Suppose we take the log (base 10) of the value 7:
import numpy as np #define original value original = 7 #take log (base 10) of original value log_original = np.log10(original) #display log (base 10) of original value log_original 0.845098
In order to get back the original value of 7, we can take the antilog by raising 10 to the power of 0.845098:
#take the antilog 10 ** log_original 7.0
By taking the antilog, we were able to obtain the original value of 7.
Example 2: Calculating the Antilog of a Natural Log
#define original value original = 7 #take natural log of original value log_original = np.log(original) #display natural log of original value log_original [1] 1.94591
In order to get back the original value of 7, we can take the antilog by raising e to the power of 1.94591:
#take the antilog np.exp(log_original) 7.0
By taking the antilog, we were able to obtain the original value of 7.