What can not be done with a component (Qt) under the LGPL (v2.1)?

Question

Qt

I want to use Qt in my application, but I don't want to redistribute the source.
Perhaps later I will want to sell it, that is, the application is commercial in the future.

Tell me, where is the border of the permitted LGPL? What can't I do to avoid falling under the (L)GPL violation?

So far, I realized that I can use dynamic linking and not modify the code of Qt itself, this should be enough for me. Is this true?

Thanks

Answer 1

Attach a license for Qt, and that's it.

Answer 2

No, the LGPL is, roughly speaking, the same GPL, only allowing the linking of third-party code.
If you do not want to open the source code of the project on Qt, you must buy a commercial license (one and a half kilodollars was a year ago, I don’t know now). There is no other way, if you do not want to violate anything.