Self doubt on regular language

Question

Infinite union of regular languages

Is not regular language.

But if there is "Union of infinite lengths regular language " then it wud be

Regular? CFL ?

Comments

then it would be regular so also CFL, because regular languages are closed under union

---

It does matter . .consider

L1 = {ab}

L2 ={aabb}

L3 = {aaabbb}

And so on. .

Now if we take union of these regular languages . .the language produced will be

L ={ a^n b^ n }