# casinf, casin, casinl

< c‎ | numeric‎ | complex

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Complex number arithmetic
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 cacos casin catan
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 Defined in header `` float complex       casinf( float complex z ); (since C99) double complex      casin( double complex z ); (since C99) long double complex casinl( long double complex z ); (since C99)

Computes the complex arc sine of `z` with branch cuts outside the interval [−1,+1] along the real axis.

## Contents

### Parameters

 z - complex argument

### Return value

The complex arc sine of `z` in the interval (−∞; ∞) along the imaginary axis and in the interval [−π/2; +π/2] along the real axis.

### Example

```#include <stdio.h>
#include <complex.h>

int main(void)
{
double complex z;

z = csin(1.0+2.0*I);
printf("csin(1.0+2.0i)            ==> %f%+fi\n", creal(z),cimag(z));

z = casin(3.165779+1.959601*I);
printf("casin(3.165779+1.959601i) ==> %f%+fi\n", creal(z),cimag(z));

return 0;
}```

Output:

```csin(1.0+2.0i)            ==> 3.165779+1.959601i
casin(3.165779+1.959601i) ==> 1.000000+2.000000i```