Add complex numbers

Author: macdems

04 More on Variables/6 Complex numbers.md

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+# Complex numbers
+
+Python has a type representing complex numbers natively (`complex`). It can be created by adding a symbol `j` to the real numbers to denote the imaginary part. For example:
+
+```python
+complex_value = 1 + 0.2j
+```
+
+On this type, you can perform normal calculations, print it, etc. But what if we want to extract only the real or imaginary part from a complex number? For this purpose, we use the *attributes* `real` and `imag`. Attributes are similar to methods: they are used by entering their names after the dot like `variable.attribute`, but without the parentheses . E.g:
+
+```python
+complex_value = 1 + 0.2j 
+
+print ("Re =", complex_value.real) 
+print ("Im =", complex_value.imag)
+```
+
+<hr/>
+
+Published under [Creative Commons Attribution-NonCommercial-ShareAlike](https://creativecommons.org/licenses/by-nc-sa/4.0/) license.