MathF.Log() Method in C# with Examples
Last Updated :
04 Apr, 2019
In C#, MathF.Log() is a MathF class method. It is used to return the logarithm of a specified number. This method can be overloaded by changing the number of the arguments passed. There are total 2 methods in the overload list of the MathF.Log() method as follows:
- MathF.Log(Single) Method
- MathF.Log(Single, Single) Method
MathF.Log(Single) Method
This method is used to return the natural (base e) logarithm of a specified number.
Syntax: public static float Log (float x);
Here, x is the specified number whose natural (base e) logarithm to be calculated and its type is System.Single.
Return Value: Returns the natural logarithm of x and its type is System.Single.
Note: Parameter x is always specified as a base 10 number. The return value is depend on the argument passed. Below are some cases:
- If the argument is positive then method will return the natural logarithm or loge(val).
- If the argument is zero, then the result is NegativeInfinity.
- If the argument is Negative(less than zero) or equal to NaN, then the result is NaN.
- If the argument is PositiveInfinity, then the result is PositiveInfinity.
- If the argument is NegativeInfinity, then the result is NaN.
Example:
using System;
class Geeks {
public static void Main(String[] args)
{
float a = 9.78f;
float b = 0f;
float c = -4.56f;
float nan = Single.NaN;
float positiveInfinity = Single.PositiveInfinity;
float negativeInfinity = Single.NegativeInfinity;
Console.WriteLine(MathF.Log(a));
Console.WriteLine(MathF.Log(b));
Console.WriteLine(MathF.Log(c));
Console.WriteLine(MathF.Log(nan));
Console.WriteLine(MathF.Log(positiveInfinity));
Console.WriteLine(MathF.Log(negativeInfinity));
}
}
|
Output:
2.280339
-Infinity
NaN
NaN
Infinity
NaN
Math.Log(Single, Single) Method
This method is used to return the logarithm of a specified number in a specified base.
Syntax: public static float Log (float x, float y);
Parameters:
x: It is the specified number whose logarithm to be calculated and its type is System.Single.
y: It is the base of the logarithm of type System.Single.
Return Value: It returns the logarithm of x and its type is System.Single.
Note: The return value is always depend on the argument passed. Below table depicts the different cases:
val |
base |
Returned Value |
val > 0 |
(0 < Base < 1) or(Base > 1) |
logbase(val) |
val < 0 |
any value |
NaN |
any value |
base < 0 |
NaN |
val != 1 |
base = 0 |
NaN |
val != 1 |
base = +ve Infinity |
NaN |
val = NaN |
any value |
NaN |
any value |
base = NaN |
NaN |
any value |
base = 1 |
NaN |
val = 0 |
(0 < Base < 1) |
+ve Infinity |
val = 0 |
base > 1 |
-ve Infinity |
val = +ve Infinity |
(0 < Base < 1) |
-ve Infinity |
val = +ve Infinity |
base > 1 |
+ve Infinity |
val = 1 |
base = 0 |
0 |
val = 1 |
base = +ve Infinity |
0 |
Example:
using System;
class Geeks {
public static void Main(String[] args)
{
Console.WriteLine(MathF.Log(4.4f, 0.4f));
Console.WriteLine(MathF.Log(0.5f, 4f));
Console.WriteLine(MathF.Log(0.9f, 1f));
Console.WriteLine(MathF.Log(0.4f, Single.NaN));
}
}
|
Output:
-1.616959
-0.5
NaN
NaN
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