I want to find out whether these sentences are grammatically incorrect:
It is more better than your book
or
It is far more better than your book
I want to find out whether these sentences are grammatically incorrect:
It is more better than your book
or
It is far more better than your book
Neither are correct. "better" is a comparative form of "good", so you do not need to (and should not) say "more better": say either:
It is better than your book.
or
It is far better than your book.
If you study the grammar point comparison forms of adjectives you will find that
1 certain adjectives have the endings -er/est
2 others use more/most before the adjective
3 some have irregular forms, e.g. good better best
Using "more better" is against normal grammar, and if it is used it is uneducated and substandard.
http://www.gingersoftware.com/content/grammar-rules/adjectives/comparing-adjectives/
I agree; it is simply redundant. It's like saying "more, more good" and you'd never (at least one can hope) say, "This book is more, more good than your book." The usage of "more better" suggests a substandard education.