cexp

Calculates the natural exponential of a complex number

```#include <complex.h>
double complex cexp ( double complex z  );
float complex cexpf ( float complex z  );
long double complex cexpl ( long double complex z  );
```

The return value of the cexp( ) function is e raised to the power of the function's argument, or ez, where e is Euler's number, 2.718281.... Furthermore, in complex mathematics, ezi = cos(z) + sin(z) x i for any complex number z.

 The natural exponential function cexp( ) is the inverse of the natural logarithm, clog( ).

#### Example

```// Demonstrate Euler's theorem in the form
// e^(I*z) = cos(z) + I * sin(z)

double complex z = 2.2 + 3.3 * I;
double complex c, d;

c = cexp( z * I );
d = ccos( z ) + csin( z ) * I ;

printf( "cexp( z*I ) yields %.2f %+.2f \xD7 I.\n",
creal(c), cimag(c) );
printf( "ccos( z ) + csin( z ) * I yields %.2f %+.2f \xD7 I.\n",
creal(d), cimag(d) );
```

This code produces the following output:

```cexp( z*I ) yields -0.02 +0.03 x I.
ccos( z ) + csin( z ) * I yields -0.02 +0.03 x I.
```