Regular Expression | Automata Theory

Question

does anyone know about regular expressions of the following languages:

1. the set of all strings starting with 000 and not ending 11
2. the set of all strings with odd string length and ending in 111
3. L6 is the set of all strings ending in 00 and containing the substring 11

I am very grateful to anyone who can help me on this case

3 regular expressions from the given case examples, and maybe how to find regular expressions from the given language

Answer 1

Every finite automata can be converted into a regular expression.

See this post for the methodology.

All 3 languages you've provided are regular! This means that you can construct finite automatons that recognise all your languages - finite automatons that can be converted into regular expressions recognising each language.

You can use this online tool or jflap if you don't want to manually convert your automatons.