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# Function as a Geometric Series

## Example

![image](https://user-images.githubusercontent.com/14041622/42362546-68667e44-8126-11e8-8e47-cf02f02bacfd.png) Solve:

* This function looks very alike the `Infinite Geometric function`:

  ![image](https://user-images.githubusercontent.com/14041622/42362580-9fdc1474-8126-11e8-982c-cae11cec4a23.png)
* So we extract the key numbers out:
  * First term: `a = 1`
  * Common Ratio: `r = -x²`
* So the infinite geometric series would be:

  ![image](https://user-images.githubusercontent.com/14041622/42362651-dd61926a-8126-11e8-9a3b-50303742f7d0.png)
* Expand the formula to be:

  ![image](https://user-images.githubusercontent.com/14041622/42362663-e9a40634-8126-11e8-90d5-57db2b669983.png)