C++ Math log1p() Function

C++ Math log1p() Function with tutorial for beginners and professionals with examples on isgreaterequal(), less(), islessequal(), islessgreater(), isunordered(), exp(), frexp(), ldexp(), log(), log10(), modf(), exp2(), expm1(), log1p(), log2(), logb(), scalbn(), scalbln() etc.

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C++ Math log1p()

The function computes the natural logarithm of a given number plus one.

Suppose a number is 'x':

log1p(x) = log(1+x);

Syntax

float log1p(float x);
double log1p(double x);
long double log1p(long double x);
double log1p(integral x);

Note: The return_type can be float, double or long double.

Parameter

x: The value of which logarithm is to be calculated.

Return value

Parameter	Return value
x>0	Positive
x=0	zero
0>x> -1	Negative
x= -1	-infinity
x<-1	Not a Number(nan)

Example 1

Let's see a simple example when the value of x is greater than zero.

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
     int x=10;
     std::cout << "Value of x is : " <<x <<std::endl;
     cout<<"log1p(x) = "<<log1p(x);
     return 0;
}

Output:

Value of x is : 10
log1p(x) = 2.3979

In this example, log1p() function computes the logarithm value when x is greater than zero.

Example 2

Let's see a simple example when the value of x is zero

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
     int x=0;
     std::cout << "Value of x is : " <<x <<std::endl;
     cout<<"log1p(x) = "<<log1p(x);
     return 0;
}

Output:

Value of x is : 0
log1p(x) = 0

In this example, log1p() function computes the logarithm value when the value of x is zero.

Example 3

Let's see a simple example when the value of x is less than zero.

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
     float x= -0.5;
     std::cout << "Value of x is : " <<x <<std::endl;
     cout<<"log1p(x) = "<<log1p(x);
     return 0;
}

Output:

Value of x is : -0.5
log1p(x) = -0.693147

In this example, log1p() function computes the logarithm value when the value of x is less than zero.

Example 4

Let's see the simple example when the value of x is -1.

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
     int x= -1;
     std::cout << "Value of x is : " <<x <<std::endl;
     cout<<"log1p(x) = "<<log1p(x);
     return 0;
}

Output:

Value of x is : -1
log1p(x) = -inf

In this example, log1p() function computes the logarithm value when the value of x is -1.

Example 5

Let's see the simple example when the value of x is less than -1.

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
    int x= -3;
    std::cout << "Value of x is : " <<x <<std::endl;
    cout<<"log1p(x) = "<<log1p(x);
    return 0;
}

Output:

Value of x is : -3
log1p(x) = -nan

In this example, log1p() function computes the logarithm value when the value of x is less than -1.

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C++ Math log1p() Function

C++ Math log1p()

Suppose a number is 'x':

Syntax

Note: The return_type can be float, double or long double.

Parameter

Return value

Example 1

Example 2

Example 3

Example 4

Example 5

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