# catanf, catan, catanl

< c‎ | numeric‎ | complex

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Complex number arithmetic
Types and the imaginary constant
Manipulation
Power and exponential functions
Trigonometric functions
 cacos casin catan
Hyperbolic functions

 Defined in header `` float complex       catanf( float complex z ); (1) (since C99) double complex      catan( double complex z ); (2) (since C99) long double complex catanl( long double complex z ); (3) (since C99) Defined in header `` #define atan( z ) (4) (since C99)
1-3) Computes the complex arc tangent of `z` with branch cuts outside the interval [−i,+i] along the imaginary axis.
4) Type-generic macro: If `z` has type long double complex, `catanl` is called. if `z` has type double complex, `catan` is called, if `z` has type float complex, `catanf` is called. If `z` is real or integer, then the macro invokes the corresponding real function (atanf, atan, atanl). If `z` is imaginary, then the macro invokes the corresponding real version of the function atanh, implementing the formula atan(iy) = i atanh(y), and the return type of the macro is imaginary.

### Parameters

 z - complex argument

### Return value

If no errors occur, complex arc tangent of `z` is returned, in the range of a strip unbounded along the imaginary axis and in the interval [−π/2; +π/2] along the real axis.

Errors and special cases are handled as if the operation is implemented by -I * catanh(I*z).