First chapter fully complete now. I had the fourth chapter already
with me, but I had to improve it as it was in accordance with the
previous settings and improper use of LaTeX. I had used  too many
dollar($) sign, which is not good to use as it tells LaTeX to do the
things forcibly. So, I had to clean-up the code for that. Also I had
lot of equations, so I just made some packages as the primary one.

1) flushleft
2) eqnarray
3) align
4) alignat

Flushleft will apply left aligning setting in all equations, and to
ident some of the lines I used \hspace.
We have monoeuations(single equal to(=)), bi-equations. For
monoequations align is used.
Coming to eqnarray and alignat, they are almost the same but with some
notable differences:

  • eqnarray has two alignment points (it’s basically just array with a
    default preamble) whereas align has one. x + y &=& z versus x + y &= z
  • eqnarray changes the spacing at the alignment points depending on
    different factors whereas align keeps it fixed (which is generally
    what you want)
  • eqnarray allows page breaks between lines and align doesn’t

Using them I fulfilling the needs of the book.