What is tanh() in D?

The tanh() function in D returns a number’s hyperbolic tangent.

Figure 1 shows the mathematical representation of the tanh() function:

Figure 1: Mathematical representation of the hyperbolic tangent function

Note: We need to import std.math in our code to use the tanh() function. We can import it like this:
import std.math.

Syntax

tanh(num)

Parameter

This function requires a number representing an angle in radians as a parameter.

To convert degrees to radians, use:

radians = degrees * ( PI / 180.0 )

Return value

tanh() returns the hyperbolic tangent of a number (radians) that is set as a parameter.

Example

The code below shows the use of the tanh() function in D:

import core.stdc.stdio;
import std.stdio;
//header required for function
import std.math;
int main()
{ 
    //positive number in radians
    writeln("The value of tanh(2.3) ", tanh(2.3));
    // negative number in radians
    writeln("The value of tanh(-2.3) ", tanh(-2.3));
    //converting the degrees angle into radians and then applying tanh()
    // degrees = 45.0
    // PI = 3.14159265
    // result first converts degrees to radians then apply tanh
    double result=tanh(45.0 * (PI / 180.0));
    writeln("The value of tanh(45.0 * (PI / 180.0)) ", result);
    
    //exceptional output
    writeln ("The value of tanh(real.infinity) : ",tanh(real.infinity));
    writeln ("The value of tanh(-real.infinity) : ",tanh(-real.infinity));
    writeln ("The value of tanh(real.nan) : ",tanh(real.nan));
    writeln ("The value of tanh(-real.nan) : ",tanh(-real.nan));
    
    return 0;
}

Explanation

Line 4: We add the header std.math required for the tanh() function.

Line 9: We calculate the hyperbolic tan of positive numbers in radians using tanh().

Line 12: We calculate the hyperbolic tan of a negative number in radians using tanh().

Line 18: We convert the degrees into radians and then apply the tanh() function. The variable result first converts degrees to radians and then applies tanh().

Line 21 onwards: We calculate the hyperbolic tan of exceptional numbers using tanh()

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