# std::cosh

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< cpp‎ | numeric‎ | math

Defined in header `<cmath>` |  |
float cosh( float arg ); | (1) |
double cosh( double arg ); | (2) |
long double cosh( long double arg ); | (3) |
double cosh( Integral arg ); | (4) | (since C++11)

Computes the hyperbolic cosine of `arg`

4) A set of overloads or a function template accepting an argument of any integral type. Equivalent to 2) (the argument is cast to double).

### Parameters

arg | - | value of a floating-point or Integral type

### Return value

If no errors occur, the hyperbolic cosine of `arg` (cosh(arg), or

earg +e-arg
2

) is returned.

If a range error due to overflow occurs, `+HUGE_VAL`, `+HUGE_VALF`, or `+HUGE_VALL` is returned.

### Error handling

Errors are reported as specified in math_errhandling

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

- if the argument is ±0, 1 is returned
- If the argument is ±∞, +∞ is returned
- if the argument is NaN, NaN is returned

### Notes

For the IEEE-compatible type double, if |arg| > 710.5, then `cosh(arg)` overflows.

### Example

    #include <iostream>
    #include <cmath>
    #include <cerrno>
    #include <cstring>
    #include <cfenv>

    #pragma STDC FENV_ACCESS ON
    int main()
    {
        std::cout << "cosh(1) = " << std::cosh(1) << '\n'
                  << "cosh(-1) = " << std::cosh(-1) << '\n'
                  << "log(sinh(1)+cosh(1)=" << std::log(std::sinh(1)+std::cosh(1)) << '\n';
        // special values
        std::cout << "cosh(+0) = " << std::cosh(0.0) << '\n'
                  << "cosh(-0) = " << std::cosh(-0.0) << '\n';
        // error handling
        errno=0; std::feclearexcept(FE_ALL_EXCEPT);
        std::cout << "cosh(710.5) = " << std::cosh(710.5) << '\n';
        if(errno == ERANGE)
            std::cout << "    errno == ERANGE: " << std::strerror(errno) << '\n';
        if(std::fetestexcept(FE_OVERFLOW))
            std::cout << "    FE_OVERFLOW raised\n";
    }

### See also

sinh | computes hyperbolic sine (sh(x)) (function)
tanh | hyperbolic tangent (function)
acosh (C++11) | computes the inverse hyperbolic cosine (arcosh(x)) (function)
cosh(std::complex) | computes hyperbolic cosine of a complex number (ch(z)) (function template)
cosh(std::valarray) | applies the function std::cosh to each element of valarray (function template)
C documentation for cosh

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