# Need serious help!

Hi Brilliant!

I have been in a bad form(not in a good frame of mind) recently. That's solely because of my inability to solve combinatorics problems. IIT-JEE is around the corner an I want to get to the level of IIT-JEE (around 250 points problems). I've read many books for IIT-JEE (combinatorics section especially) but still I feel there's some flaw in my understanding of concepts in combinatorics. I do not go to any coaching now as I feel self studying is more important at this time. That's why I'm asking you for help. I do not have deep interest in combinatorics as much I have in calculus. My inability to solve problems in combinatorics has lead to frustration and poor performance in other subjects. I don't want to ruin my IIT-JEE. Please help.

Please share good techniques (which can be generally used for problem solving), theories (which generally come in exams) and some sources.

Another problem is time factor. I don't have much time to read fat books, etc.

Any sort of help will be appreciated :)

4 years, 5 months ago

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Try to understand these by putting a strain on your brain

1.Inclusion Exclusion Principles(very useful for problems involving functions in combinatorics)

2.Derrangements

3.Difference between division and distribution

4.Difference in permutations and combinations of identical and unidentical objects

5.Circular permutations

Yes combinatorics does require a bit of jugglery. Try to solve each and every possible question of combinatorics of previous year jee papers after learning the above concepts. We are always here.. ;)

- 4 years, 5 months ago

ThanksI I shall start from now itself! (:

- 4 years, 5 months ago

I would suggest Principles and Techniques in Combinatorics by Chen Chuan-Chong, Khee-Meng Koh

It covers all the techniques required for JEE combinatorics, and has lots of solved examples.

- 4 years, 5 months ago

That book is too expensive. Do you have a PDF of it?

- 4 years, 5 months ago

I have. I used it for RMO long back. (Again going to start using it :P)

- 4 years, 5 months ago

If u have pdf pls share

- 4 years, 5 months ago

- 4 years, 5 months ago

Thanks!!

- 4 years, 5 months ago

Thanks I got the PDF. It is really a good book. (:

- 4 years, 5 months ago

- 4 years, 5 months ago

You are welcome :)

- 4 years, 5 months ago

@Sandeep Bhardwaj One your Quick Notes is needed. :)

- 4 years, 5 months ago

Try Brilliant Wikis.

- 4 years, 5 months ago

Yes I saw them (:

- 4 years, 5 months ago

Okay, since you mentioned JEE only, I'll tell you the way to practice that worked for me - the Archives (past JEE papers). Try solving every combinatorics question, and if you can't, read the theory/solution and proceed. Try this out, and tell me if it works.

- 4 years, 5 months ago

Sir if u have time do watch mohit tyagi on youtube . He is a very good teacher and will be quite helpfull to u in your P & C

- 4 years, 5 months ago

- 4 years, 5 months ago

Have u seen any of them they are indeed very good

- 4 years, 5 months ago

This might help. :)

- 4 years, 5 months ago

Thanks!

- 4 years, 5 months ago

This might be too easy

Practice all of these

Hope it helps.

- 4 years, 5 months ago

I saw many of them.

- 4 years, 5 months ago

Great, then practice more. All the best! :)

- 4 years, 5 months ago

Thanks!

- 4 years, 5 months ago

btw where are you now?

- 4 years, 5 months ago

I'm in Bangalore. My dad is transferred. I'll come back to Mumbai on 10 May.

- 4 years, 5 months ago

So you wont give any fiitjee test now?

- 4 years, 5 months ago

Apparently no. But I'll give the last one on 15 May.

- 4 years, 5 months ago

Okay! How was mains?

- 4 years, 5 months ago

- 4 years, 5 months ago

Okay!

- 4 years, 5 months ago

See this

- 4 years, 5 months ago

Can you please tell me some sources on the topics of special functions (polygamma, gamma,etc) and summation...it would be really helpful

- 4 years, 2 months ago

Explore the wiki pages.

- 4 years, 2 months ago

Thanks for the reply! But it seems that link is not working now..

- 4 years, 2 months ago

Remember these(some of them might be quite easy for you): 1)Whenever solving P and C probs,this 'mantra' works for me,First,find out the number of ways to 'combinate'(if you know what I mean),and then permute it.2)Always remember that whenever you are taking product,you are permuting.3)Try this.  I hope this helps!

- 4 years, 5 months ago

Thanks!

- 4 years, 5 months ago

I sent you something on slack. Check it out. Your PnC level will boost 5 times with that.

- 4 years, 5 months ago

Do you mind sharing it here too? Thanks!

- 4 years, 5 months ago

That video is in Hindi. Do you know Hindi?

- 4 years, 5 months ago