The objective of this note is to know and tell about the concepts, techniques or tricks which may be helpful during our Jee-prepration and are rather not that popular ( i.e you do not learn them commonly in school or maybe not at coaching too .) so, it will just take few seconds to write down (Our target would be to give at least a concept daily ) but it will help us all ! you may also write something important ( only related to study ) so that you may see it later , It would be great if you all make this note an important one such that we will see it a day or two before jee advanced ! \[\] Rules : if you are contributing something , write it's number after 2 hashtags and comment and if you are just commenting , write normally ! \[\] ##Enjoy !

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TopNewest## 5 \[\] Whobbling coin : concept is very important, you can learn it here : coin or here .....there are some nice question on brillant related to it too .............. 1 or 2 { although , i solved both of them without learning the concept :P }

– Brilliant Member · 9 months, 1 week agoLog in to reply

– Harsh Shrivastava · 9 months, 1 week ago

It is not in the syllabus I guess?Log in to reply

– Brilliant Member · 9 months, 1 week ago

yes , but in jee-advanced question can be asked as we saw in jee adv. -2016 that they are shifting their focus from normal to some good level physics ! :)Log in to reply

## 4

## Using Feynman's method of integration can be useful in scenarios where there is a natural logarithm on the numerator of the integrand.

– Harsh Shrivastava · 9 months, 1 week agoLog in to reply

## method of this trick is to differentiate the integral w.r.t to a constant and then integrate normally !!

– Brilliant Member · 8 months, 3 weeks agoLog in to reply

For example,consider this :

\(\displaystyle \int_{0}^{1}\dfrac{1-x^{2016}}{\ln x} dx\)

It can be easily solved by using feynman's method! – Harsh Shrivastava · 8 months, 3 weeks ago

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– Brilliant Member · 8 months, 3 weeks ago

care to show , how ?Log in to reply

\(\implies F'(a) = \displaystyle \int_{0}^{1} \dfrac{-x^{a} \ln x}{\ln x}dx = \displaystyle \int_{0}^{1} -x^{a}dx\)

Now rest is easy i guess. – Harsh Shrivastava · 8 months, 3 weeks ago

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@Harsh Shrivastava both of them yield different result ! :O , first will give -log(2017) while second one 1/2017 , there is difference of that log ! – Brilliant Member · 8 months, 3 weeks ago

but broLog in to reply

– Brilliant Member · 8 months, 3 weeks ago

your concept is wrong bro !Log in to reply

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I'll give some awesome application of these tricks in a few days. – Harsh Shrivastava · 9 months, 1 week ago

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Gone are the days when people used to be online, now where are the gone.

Please contribute guyz @Aniket Sanghi @Prakhar Bindal

BTW how is your preparation going? – Harsh Shrivastava · 9 months, 1 week ago

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https://brilliant.org/problems/frac1falling-space-rod/

i had taken a note of it some time before – Prakhar Bindal · 9 months, 1 week ago

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– Prakhar Bindal · 9 months, 1 week ago

Actually i hardly see my notifications these days. just when i am bored i open brilliant see a problem take a note of it and then go back again to my room for solvingLog in to reply

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Best of luck! – Harsh Shrivastava · 9 months, 1 week ago

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This problem's solution contains some awesome results that are hell useful. – Harsh Shrivastava · 9 months, 1 week ago

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– Brilliant Member · 9 months, 1 week ago

solved it, was nice !Log in to reply

## 3 \[\] Descartes rule of signs : Again , not that uncommon but useful "trick for finding the roots of a quadratic ! You can learn it here or here

– Brilliant Member · 9 months, 2 weeks agoLog in to reply

## 9 Some expansions and special series and suggest you remember them too ! :) taylor and basel problem types

– Brilliant Member · 8 months, 3 weeks agoLog in to reply

## 7 \[\] i am tired of writing "not that uncommon" but here are cauchy-swartz and generalized mean theorm

– Brilliant Member · 9 months, 1 week agoLog in to reply

– Harsh Shrivastava · 8 months, 3 weeks ago

Cauchy schwarz is really really awesome and useful for manyy problems!Log in to reply

## 6 \[\] common sense :P

– Brilliant Member · 9 months, 1 week agoLog in to reply

– Harsh Shrivastava · 9 months, 1 week ago

I have posted our challenge problem,do try it!Log in to reply

## 2 \[\] Abel's theorm for power series : you can learn it here Abel it is useful for calculation of some power series expansion ! you can see other theorms given by Niels Henrik Abel in the related links on wikipedia !

– Brilliant Member · 9 months, 2 weeks agoLog in to reply

## 1 \[\] I will begin by giving information about a method called method of images(not that rare but helpful sometimes !) \[\] for hindi speaker this will be the best explanation or maybe this : wiki \[\] there is a nice question on brilliant too on it here , it deals with the quantitative analysis of charge induced on an equipotential surface !

– Brilliant Member · 9 months, 2 weeks agoLog in to reply

– Kishore S Shenoy · 9 months, 2 weeks ago

Images are useful in many problems in I E Irodov's bookLog in to reply

– Brilliant Member · 9 months, 2 weeks ago

yeah ! that's why i told it and also wrote (not so rare , if you have some concept to share , do write it ! )Log in to reply

– Kishore S Shenoy · 9 months, 2 weeks ago

I have a method which will solve Irodov's Mechanics Q1.82 in 3 steps. How did you do it?Log in to reply

@Kishore S Shenoy ? – Brilliant Member · 9 months, 2 weeks ago

drew fbd's and constraint of string length i did in 3-4 steps too ! which method do you wanna propose broLog in to reply

– Kishore S Shenoy · 9 months, 2 weeks ago

Balanced horizontal forces and acceleration along the wedge to get acceleration.Log in to reply

## 8 From me too bro : link

– Hiroto Kun · 8 months, 4 weeks agoLog in to reply

what do you say : @Prakhar Bindal @Kishore S Shenoy @Avi Ghanshani @Aniket Sanghi @Rajbir Malik @saharsh rathi @Rajdeep Dhingra @neelesh vij @aryan goyat @Rudraksh Sisodia @Swagat Panda help by contributing in any subject ( PCM ) thnx ! – Brilliant Member · 9 months, 2 weeks ago

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– Rudraksh Sisodia · 9 months, 2 weeks ago

thanks for mentioning me , bro this sounds cool .. i have some stuff related to the electrical ckts , capacitors and lemme find out more ..Log in to reply

– Brilliant Member · 8 months, 3 weeks ago

aren't you gonna post ?Log in to reply