std::cos, std::cosf, std::cosl
Defined in header <cmath> |
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(1) | ||
float cos ( float arg ); |
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float cosf( float arg ); |
(since C++11) | |
double cos ( double arg ); |
(2) | |
(3) | ||
long double cos ( long double arg ); |
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long double cosl( long double arg ); |
(since C++11) | |
double cos ( IntegralType arg ); |
(4) | (since C++11) |
arg
(measured in radians).
double
).
Parameters
arg | - | value representing angle in radians, of a floating-point or Integral type |
Return value
If no errors occur, the cosine of arg
(cos(arg)) in the range [-1 ; +1], is returned.
The result may have little or no significance if the magnitude of |
(until C++11) |
If a domain error occurs, an implementation-defined value is returned (NaN where supported).
If a range error occurs due to underflow, the correct result (after rounding) 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, the result is 1.0
- if the argument is ±∞, NaN is returned and
FE_INVALID
is raised - if the argument is NaN, NaN is returned
Notes
The case where the argument is infinite is not specified to be a domain error in C, but it is defined as a domain error in POSIX.
Example
#include <iostream> #include <cmath> #include <cerrno> #include <cfenv> #pragma STDC FENV_ACCESS ON const double pi = std::acos(-1); int main() { // typical usage std::cout << "cos(pi/3) = " << std::cos(pi/3) << '\n' << "cos(pi/2) = " << std::cos(pi/2) << '\n' << "cos(-3*pi/4) = " << std::cos(-3*pi/4) << '\n'; // special values std::cout << "cos(+0) = " << std::cos(0.0) << '\n' << "cos(-0) = " << std::cos(-0.0) << '\n'; // error handling std::feclearexcept(FE_ALL_EXCEPT); std::cout << "cos(INFINITY) = " << std::cos(INFINITY) << '\n'; if (std::fetestexcept(FE_INVALID)) std::cout << " FE_INVALID raised\n"; }
Possible output:
cos(pi/3) = 0.5 cos(pi/2) = 6.12323e-17 cos(-3*pi/4) = -0.707107 cos(+0) = 1 cos(-0) = 1 cos(INFINITY) = -nan FE_INVALID raised
See also
(C++11)(C++11)
|
computes sine (\({\small\sin{x} }\)sin(x)) (function) |
(C++11)(C++11)
|
computes tangent (\({\small\tan{x} }\)tan(x)) (function) |
(C++11)(C++11)
|
computes arc cosine (\({\small\arccos{x} }\)arccos(x)) (function) |
computes cosine of a complex number (\({\small\cos{z} }\)cos(z)) (function template) |
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applies the function std::cos to each element of valarray (function template) |
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C documentation for cos |
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