Advertisement

Tanh calculator

Explore tanh as a bounded function of a dimensionless real number. Compare its slope and companion functions, or work backwards from a value between -1 and 1.

Calculator

Argument x
1.00000000
tanh(x)
0.76159416
Local derivative
0.41997434
sinh(x)
1.17520119
cosh(x)
1.54308063
coth(x)
1.3130352854993315
csch(x)
0.8509181282393216
sech(x)
0.64805427
Tanh and its slope at integer arguments
xtanh(x)Derivative
-3.00000000-0.995054750.00986604
-2.00000000-0.964027580.07065082
-1.00000000-0.761594160.41997434
0.000000000.000000001.00000000
1.000000000.761594160.41997434
2.000000000.964027580.07065082
3.000000000.995054750.00986604

Advertisement

How this calculator works

Hyperbolic tangent divides hyperbolic sine by hyperbolic cosine. Its graph passes through zero, increases everywhere and approaches horizontal limits at -1 and 1. The derivative readout measures how sensitive the output is to a small change in x. The table shows this slope shrinking away from zero. All six companion values are evaluated at the same argument; reciprocal functions that divide by zero are marked undefined. Forward inputs are limited to -700 through 700 to keep sinh and cosh finite.

Formula

tanh x = sinh x / cosh x = (exp(2x)-1)/(exp(2x)+1); d(tanh x)/dx = sech²x; atanh y = ln((1+y)/(1-y))/2.

Worked example

At x = ln 2, sinh x = 3/4 and cosh x = 5/4. Therefore tanh x = 3/5 = 0.6 and the derivative is (4/5)² = 0.64. Inverse mode maps -0.6 to -ln 2.

Advertisement

Frequently asked questions

Should I enter degrees or radians?

Neither conversion is applied. The argument is a dimensionless parameter rather than a circular angle.

Can tanh equal one?

For finite real x it is strictly below one. Floating-point arithmetic may round the value to one for large positive arguments; inverse mode still rejects one.

Why are coth and csch undefined at zero?

They divide by tanh(0) and sinh(0), respectively. Both denominators are zero.

Sources

Advertisement