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      std::cos,std::cosf,std::cosl

      From cppreference.com
      <cpp‎ |numeric‎ |math
       
       
       
      Common mathematical functions
      Nearest integer floating point operations
      (C++11)(C++11)(C++11)
      (C++11)
      (C++11)
      (C++11)(C++11)(C++11)
      Floating point manipulation functions
      (C++11)(C++11)
      (C++11)
      (C++11)
      Classification and comparison
      (C++11)
      (C++11)
      (C++11)
      (C++11)
      (C++11)
      (C++11)
      Types
      (C++11)
      (C++11)
      (C++11)
      Macro constants
       
      Defined in header<cmath>
      (1)
      float       cos(float num);

      double      cos(double num);

      longdouble cos(longdouble num);
      (until C++23)
      /*floating-point-type*/
                  cos(/*floating-point-type*/ num);
      (since C++23)
      (constexpr since C++26)
      float       cosf(float num);
      (2)(since C++11)
      (constexpr since C++26)
      longdouble cosl(longdouble 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>

                  cos(const V& v_num);
      (S)(since C++26)
      Defined in header<cmath>
      template<class Integer>
      double      cos( Integer num);
      (A)(constexpr since C++26)
      1-3) Computes the cosine ofnum (measured in radians). The library provides overloads ofstd::cos for all cv-unqualified floating-point types as the type of the parameter.(since C++23)
      S) The SIMD overload performs an element-wisestd::cos onv_num.
      (Seemath-floating-point anddeduced-simd-t for their definitions.)
      (since C++26)
      A) Additional overloads are provided for all integer types, which are treated asdouble.
      (since C++11)

      Contents

      [edit]Parameters

      num - floating-point or integer value representing angle in radians

      [edit]Return value

      If no errors occur, the cosine ofnum (cos(num)) in the range[-1.0+1.0], is returned.

      The result may have little or no significance if the magnitude ofnum is large.

      (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.

      [edit]Error handling

      Errors are reported as specified inmath_errhandling.

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

      • if the argument is ±0, the result is1.0.
      • if the argument is ±∞, NaN is returned andFE_INVALID is raised.
      • if the argument is NaN, NaN is returned.

      [edit]Notes

      The case where the argument is infinite is not specified to be a domain error in C, but it is defined as adomain error in POSIX.

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

      [edit]Example

      Run this code
      #include <cerrno>#include <cfenv>#include <cmath>#include <iomanip>#include <iostream>#include <numbers> // #pragma STDC FENV_ACCESS ON constexprdouble pi=std::numbers::pi;// or std::acos(-1) before C++20 constexprdouble your_cos(double x){double cos{1}, pow{x};for(auto fac{1ull}, n{1ull}; n!=19; fac*=++n, pow*= x)if((n&1)==0)            cos+=(n&2?-pow: pow)/ fac;return cos;} int main(){std::cout<<std::setprecision(10)<<std::showpos<<"Typical usage:\n"<<"std::cos(pi/3) = "<< std::cos(pi/3)<<'\n'<<"your cos(pi/3) = "<< your_cos(pi/3)<<'\n'<<"std::cos(pi/2) = "<< std::cos(pi/2)<<'\n'<<"your cos(pi/2) = "<< your_cos(pi/2)<<'\n'<<"std::cos(-3*pi/4) = "<< std::cos(-3* pi/4)<<'\n'<<"your cos(-3*pi/4) = "<< your_cos(-3* pi/4)<<'\n'<<"Special values:\n"<<"std::cos(+0) = "<< std::cos(0.0)<<'\n'<<"std::cos(-0) = "<< std::cos(-0.0)<<'\n'; // error handlingstd::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:

      Typical usage:std::cos(pi/3) = +0.5your cos(pi/3) = +0.5std::cos(pi/2) = +6.123233996e-17your cos(pi/2) = -3.373452105e-15std::cos(-3*pi/4) = -0.7071067812your cos(-3*pi/4) = -0.7071067812Special values:std::cos(+0) = +1std::cos(-0) = +1cos(INFINITY) = -nan    FE_INVALID raised

      [edit]See also

      (C++11)(C++11)
      computes sine (\({\small\sin{x}}\)sin(x))
      (function)[edit]
      (C++11)(C++11)
      computes tangent (\({\small\tan{x}}\)tan(x))
      (function)[edit]
      (C++11)(C++11)
      computes arc cosine (\({\small\arccos{x}}\)arccos(x))
      (function)[edit]
      computes cosine of a complex number (\({\small\cos{z}}\)cos(z))
      (function template)[edit]
      applies the functionstd::cos to each element of valarray
      (function template)[edit]
      Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/numeric/math/cos&oldid=162683"

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