Actually, I am not convinced of the results of those studies. They made a rather limited sampling of various topics, and they were not extensive at all as far as topics involving physics are concerned.

But there is another issue here. Textbooks, encyclopedias, etc. are written by people who also pay attention to HOW the material is presented. There is an emphasis on pedagogy. This is why some people prefer one text over another, not because of variation in content, but rather due to variation in the presentation. The fractured presentation of entries in Wikipedia have often produced confusing, disjointed, and unorganized presentation of the material. There is very little thought given to pedagogy, especially when more than one unrelated authors are doing the editing.

This is what I meant by a fundamental flaw in the philosophy of Wikipedia.

Zz.

Nice .

Hope everything is OK.

Believe me, it's quite time consuming learning maths and apps; and in my case it really kind of deprived from other stuff.

To succeed in maths you need to be dedicated and sometimes it takes its toll on other stuff.

For serious issues, you should not rely on a single source.
This rule can be generalized, there is nothing special about Wikipedia. Various studies have shown that wikipedia has a similar or lower error rate as conventional encyclopedias. At the same time, it is often much more up to date, and significantly larger. I don't remember comparisons between Wikipedia and newspapers/magazines, but I would expect that Wikipedia wins there.
To get a lower error rate, you need specialized scientific journals and/or publications. An unfair comparison, in my opinion.