Difference between revisions of "cpp/numeric/complex/cos"
From cppreference.com
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If no errors occur, the complex cosine of {{tt|z}} is returned. | If no errors occur, the complex cosine of {{tt|z}} is returned. | ||
| − | Errors and special cases are handled as if the operation is implemented by {{ | + | Errors and special cases are handled as if the operation is implemented by {{tt|[[cpp/numeric/complex/cosh|std::cosh]](i*z)}}, where {{tt|i}} is the imaginary unit. |
===Notes=== | ===Notes=== | ||
Revision as of 17:23, 17 October 2014
| Defined in header <complex>
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| template< class T > complex<T> cos( const complex<T>& z ); |
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Computes complex cosine of a complex value z.
Contents |
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)) (function template) | |
| computes tangent of a complex number (tan(z)) (function template) | |
| (C++11) |
computes arc cosine of a complex number (arccos(z)) (function template) |
| (C++11)(C++11) |
computes cosine (cos(x)) (function) |
| applies the function std::cos to each element of valarray (function template) | |
| C documentation for ccos
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