The function is the following:

[![enter image description here](https://i.stack.imgur.com/nYh9q.png)](https://i.stack.imgur.com/nYh9q.png)

The objetive of the exercise is to calculate
[![enter image description here](https://i.stack.imgur.com/4bNyD.png)](https://i.stack.imgur.com/4bNyD.png).

For that I used the following steps:

[![enter image description here](https://i.stack.imgur.com/4yxdY.png)](https://i.stack.imgur.com/4yxdY.png)

My resolution is wrong because the result has to be 2.