For complex numbers, the exponential value is calculated as follows:

  ```
  e^(x+iy) = e^x * e^iy = e^x * (cos y + i sin y)
  ```

  Let's consider complex number 1+1j as an example.
  e^1 * (cos 1 + i sin 1) = 2.7182818284590 * (0.54030230586+0.8414709848j)

  ```python
  x = tf.constant(1 + 1j)
  tf.math.exp(x) ==> 1.4686939399158851+2.2873552871788423j
  ```
  }];