std::cos(std::complex) (3) - Linux Man Pages

std::cos(std::complex): std::cos(std::complex)

NAME

std::cos(std::complex) - std::cos(std::complex)

Synopsis


Defined in header <complex>
template< class T >
complex<T> cos( const complex<T>& z );


Computes complex cosine of a complex value z.

Parameters


z - complex value

Return value


If no errors occur, the complex cosine of z is returned.
Errors and special cases are handled as if the operation is implemented by std::cosh(i*z), where i is the imaginary unit.

Notes


The cosine is an entire function on the complex plane, and has no branch cuts.
Mathematical definition of the cosine is cos z =


eiz
+e-iz
2

Example


// Run this code


  #include <iostream>
  #include <cmath>
  #include <complex>


  int main()
  {
      std::cout << std::fixed;
      std::complex<double> z(1, 0); // behaves like real cosine along the real line
      std::cout << "cos" << z << " = " << std::cos(z)
                << " ( cos(1) = " << std::cos(1) << ")\n";


      std::complex<double> z2(0, 1); // behaves like real cosh along the imaginary line
      std::cout << "cos" << z2 << " = " << std::cos(z2)
                << " (cosh(1) = " << std::cosh(1) << ")\n";
  }

Output:


  cos(1.000000,0.000000) = (0.540302,-0.000000) ( cos(1) = 0.540302)
  cos(0.000000,1.000000) = (1.543081,-0.000000) (cosh(1) = 1.543081)

See also


                   computes sine of a complex number (sin(z))
sin(std::complex) (function template)
                   computes tangent of a complex number (tan(z))
tan(std::complex) (function template)


acos(std::complex) computes arc cosine of a complex number (arccos(z))
                   (function template)
(C++11)


cos
cosf
cosl computes cosine (cos(x))
                   (function)


(C++11)
(C++11)
                   applies the function std::cos to each element of valarray
cos(std::valarray) (function template)