# catanf, catan, catanl

< c‎ | numeric‎ | complex

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 cacos casin catan
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 Defined in header `` float complex       catanf( float complex z ); (since C99) double complex      catan( double complex z ); (since C99) long double complex catanl( long double complex z ); (since C99)

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

## Contents

### Parameters

 z - complex argument

### Return value

The complex arc tangent 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()
{
double complex z;

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

z = catan(0.033813+1.014794*I);
printf("catan(0.033813+1.014794i) ==> %f%+fi\n", creal(z),cimag(z));

return 0;
}```

Output:

```ctan(1.0+2.0i)            ==> 0.033813+1.014794i
catan(0.033813+1.014794i) ==> 1.000004+1.999996i```