2

Using geometric region functions:

```
RegionPlot@
ImplicitRegion[
1 + x^2 - y^2 == 3 Log[1 + x^2],
{{x, -1.5, 1.5}, {y, -1.5, 1.5}}
]
```

See also: Plotting implicitly-defined space curves for other interesting approaches.

What do you think about closing this topic as a duplicate of https://mathematica.stackexchange.com/q/34668/5478 and moving your answer there for completeness?

– Kuba – 2018-04-23T08:48:36.677@Kuba I agree, your suggestion sounds reasonable to me. – MarcoB – 2018-04-23T14:09:07.960

kuba @MarcoB seems like a good idea, I´ll do it. – Damian Muciño – 2018-04-23T17:27:30.370

2

```
ContourPlot[1+x^2-y^2==3Log[1+x^2],{x,-1.5,1.5},{y,-1.5,1.5}]
```

5Please post copyable code so that users can easily play with it. – Henrik Schumacher – 2018-04-22T22:01:29.577

@HenrikSchumacher sorry this was my first time posting a question, I´ll do it in the next. – Damian Muciño – 2018-04-23T17:23:05.687

Mkay... I'll let you off with that... - this time. ;) – Henrik Schumacher – 2018-04-23T17:25:41.553