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      std::cos(std::complex)

      From cppreference.com
      <cpp‎ |numeric‎ |complex
       
       
       
       
      Defined in header<complex>
      template<class T>
      complex<T> cos(const complex<T>& z);

      Computes complex cosine of a complex valuez.

      Contents

      [edit]Parameters

      z - complex value

      [edit]Return value

      If no errors occur, the complex cosine ofz is returned.

      Errors and special cases are handled as if the operation is implemented bystd::cosh(i * z), wherei is the imaginary unit.

      [edit]Notes

      The cosine is an entire function on the complex plane, and has no branch cuts.

      Mathematical definition of the cosine iscos z =
      eiz
      +e-iz
      2
      .

      [edit]Example

      Run this code
      #include <cmath>#include <complex>#include <iostream> int main(){std::cout<<std::fixed;std::complex<double> z(1.0,0.0);// behaves like real cosine along the real linestd::cout<<"cos"<< z<<" = "<<std::cos(z)<<" ( cos(1) = "<<std::cos(1)<<")\n"; std::complex<double> z2(0.0,1.0);// behaves like real cosh along the imaginary linestd::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)

      [edit]See also

      computes sine of a complex number (\({\small\sin{z}}\)sin(z))
      (function template)[edit]
      computes tangent of a complex number (\({\small\tan{z}}\)tan(z))
      (function template)[edit]
      computes arc cosine of a complex number (\({\small\arccos{z}}\)arccos(z))
      (function template)[edit]
      (C++11)(C++11)
      computes cosine (\({\small\cos{x}}\)cos(x))
      (function)[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/complex/cos&oldid=150846"

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