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Variants

std:: cosh, std:: coshf, std:: coshl

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C++
Numerics library
Common mathematical functions
Nearest integer floating point operations
(C++11)
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(C++11) (C++11) (C++11)
Floating point manipulation functions
(C++11) (C++11)
(C++11)
(C++11)
Classification and comparison
(C++11)
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Types
(C++11)
(C++11)
(C++11)
Macro constants
Defined in header <cmath>
(1)
float cosh ( float num ) ;

double cosh ( double num ) ;

long double cosh ( long double num ) ;
(until C++23)
/*floating-point-type*/
cosh ( /*floating-point-type*/ num ) ;
(since C++23)
(constexpr since C++26)
float coshf ( float num ) ;
(2) (since C++11)
(constexpr since C++26)
long double coshl ( long double num ) ;
(3) (since C++11)
(constexpr since C++26)
SIMD overload (since C++26)
Defined in header <simd>
template < /*math-floating-point*/ V >

constexpr /*deduced-simd-t*/ < V >

cosh ( const V & v_num ) ;
(S) (since C++26)
Defined in header <cmath>
template < class Integer >
double cosh ( Integer num ) ;
(A) (constexpr since C++26)
1-3) Computes the hyperbolic cosine of num . The library provides overloads of std::cosh for all cv-unqualified floating-point types as the type of the parameter. (since C++23)
S) The SIMD overload performs an element-wise std::cosh on v_num .
(See math-floating-point and deduced-simd-t for their definitions.)
(since C++26)
A) Additional overloads are provided for all integer types, which are treated as double .
(since C++11)

Contents

Parameters

num - floating-point or integer value

Return value

If no errors occur, the hyperbolic cosine of num ( cosh(num) , or
e num
+e -num
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 |num| > 710.5 , then std :: cosh ( num ) overflows.

The additional overloads are not required to be provided exactly as (A) . They only need to be sufficient to ensure that for their argument num of integer type, std :: cosh ( num ) has the same effect as std :: cosh ( static_cast < double > ( num ) ) .

Example

Run this code 
#include <cerrno>
#include <cfenv>
#include <cmath>
#include <cstring>
#include <iostream>
// #pragma STDC FENV_ACCESS ON
int main()
{
    const double x = 42;
    std::cout << "cosh(1) = " << std::cosh(1) << '\n'
              << "cosh(-1) = " << std::cosh(-1) << '\n'
              << "log(sinh(" << x << ")+cosh(" << x << ")) = "
              << std::log(std::sinh(x) + std::cosh(x)) << '\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";
}

Possible output: 

cosh(1) = 1.54308
cosh(-1) = 1.54308
log(sinh(42)+cosh(42)) = 42
cosh(+0) = 1
cosh(-0) = 1
cosh(710.5) = inf
    errno == ERANGE: Numerical result out of range
    FE_OVERFLOW raised

See also

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