# std::sin(std::complex)

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< cpp‎ | numeric‎ | complex

Defined in header `<complex>` |  |
template< class T > complex<T> sin( const complex<T>& z ); |  |

Computes complex sine of a complex value z.

### Parameters

z | - | complex value

### Return value

If no errors occur, the complex sine of z is returned.

Errors and special cases are handled as if the operation is implemented by -i *`` `std::sinh`(i * z), where `i` is the imaginary unit.

### Notes

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

Mathematical definition of the sine is sin z =

eiz -e-iz
2i

.

### 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 sine along the real line
        std::cout << "sin" << z << " = " << std::sin(z)
                  << " ( sin(1) = " << std::sin(1) << ")\n";

        std::complex<double> z2(0.0, 1.0); // behaves like sinh along the imaginary line
        std::cout << "sin" << z2 << " = " << std::sin(z2)
                  << " (sinh(1) = " << std::sinh(1) << ")\n";
    }

Output:

    sin(1.000000,0.000000) = (0.841471,0.000000) ( sin(1) = 0.841471)
    sin(0.000000,1.000000) = (0.000000,1.175201) (sinh(1) = 1.175201)

### See also

cos(std::complex) | computes cosine of a complex number (\({\small\cos{z} }\)cos(z)) (function template)
tan(std::complex) | computes tangent of a complex number (\({\small\tan{z} }\)tan(z)) (function template)
asin(std::complex) (C++11) | computes arc sine of a complex number (\({\small\arcsin{z} }\)arcsin(z)) (function template)
sin sinf sinl (C++11)(C++11) | computes sine (\({\small\sin{x} }\)sin(x)) (function)
sin(std::valarray) | applies the function std::sin to each element of valarray (function template)

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