How should my auto-correlation plot look like for a mean reverting process? From what I have recently learned, auto-correlation should be low and should decay fast enough. But when I run the following command in R

```
acf(sin(1:100)) #mean reverting process 

```

![plot of autocorrelation for sin(x)](https://i.stack.imgur.com/3bsst.jpg)

I see that auto-correlation is very different from zero and intuitively makes a lot of sense, when values are high it becomes negative and when values are low it becomes positive. So I'm confused which one is correct: zero auto-correlation or similar profile as above.