How to build logic to make context free grammar?

[shivajikobardan]

Homework Statement

Context free grammar

Relevant Equations

None

I already have the solution.

I also have another solution for this-:

S->AB

A->aA/a

B->ab/aBb

But my issue is I am memorizing them, I am not understanding how this came up. Please explain the logic building behind this.

 

[lewando]

I don't think there is any "logic" to deriving a specific string of terminals from the "rules". I am sure there are exhaustive methods that can be performed by a machine. For us, it is kind of a puzzle.

 

[shivajikobardan]

I mean just some initution to understand why we came to this solution I mean would be helpful. I know there is no mechanical process for this. It is all practice. But my problem is I am confused while practicing. (I am clear about this tho so don't waste time on this now).