The tanh() method calculates the hyperbolic tangent of the specified number and returns it.
Example
// hyperbolic tangent of 1
let number = Math.tanh(1);
console.log(number); 
// Output: 0.7615941559557649
tanh() Syntax
The syntax of the Math.tanh() method is:
Math.tanh(number)
Here, tanh() is a static method. Hence, we are accessing the method using the class name, Math.
tanh() Parameters
The tanh() method takes a single parameter:
number- whose hyperbolic tangent is to be calculated
tanh() Return Value
The tanh() method returns:
- hyperbolic tangent of the given argument 
number - NaN (Not a Number) for a non-numeric argument
 
Example 1: JavaScript Math.tanh()
// hyperbolic tangent of negative number
let number1 = Math.tanh(-1);
console.log(number1); 
// hyperbolic tangent of zero
let number2 = Math.tanh(0);
console.log(number2);
// hyperbolic tangent of positive number
let number3 = Math.tanh(2);
console.log(number3); 
// Output:
// -0.7615941559557649
// 0
// 0.9640275800758169
In the above example, the Math.tanh() method computes the hyperbolic tangent of 
-1(negative number) - results in -0.76159415595576490(zero) - results in 02(positive number) - results in 0.9640275800758169
Note: Mathematically, the hyperbolic tangent is equal to (ex - e-x)/(ex + e-x).
Example 2: Math.tanh() with Infinity Values
// tanh() with negative infinity
let number1 = Math.tanh(-Infinity);
console.log(number1);
// Output: -1
// tanh() with positive infinity 
let number2 = Math.tanh(Infinity);
console.log(number2);
// Output: 1
Here, the tanh() method, when used with infinities, returns -1 (if the parameter is -Infinity) and 1 (if the parameter is Infinity).
Example 3: Math.tanh() with Non-Numeric Argument
let string = "Harry";
// tanh() with string argument
let value = Math.tanh(string);
console.log(value);
// Output: NaN
In the above example, we have tried to calculate the hyperbolic tangent of the string "Harry". That's why we get NaN as the output.
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