Suppose we have to find the no. of permutations by arranging the four letters of the word DOOR. If we apply simple permutation formula here, our answer will be 4! But this is wrong Why? It is because O comes two times in every word which is made by shuffling these letters. For example, ORDO…

# Category: Blog

## CHANGING MULTIPLICATION INTO SUBTRACTION !!

Note from the admin : This is not a trick or an easy method to solve multiplication.It is just for those who really appreciate the beauty of mathematics. Also, strict action will be taken if he/she uses it on any other site,not even youtube. So, let’s get started : If we want to multiply 12…

## Why sin^2(x) + cos^2(x) = 1 ?

Why sin^2(x) + cos^2(x) = 1 ? Sinx means perpendicular upon hypotenuse Cosx means Base upon hypotenuse Let’s take a unit circle, A unit circle simply means a circle with radius 1 unit. It may be 1cm, 1m or any other unit. Now let’s take a point on this circle, say P. Now let’s draw…

## SEQUENCE AND SERIES FOR CLASS 11

TOPICS TO BE COVERED : –>nth term of an AP –>sum of AP upto n terms –>arithmetic mean –>nth term of a GP –>sum of GP upto n terms Let’s start with a game of sequences, basically you have to tell the next term of these sequences : 1,2,3,4,___ 2,4,6,___ 3,6,9,___ Of course we can…

## PERMUTATIONS FOR CLASS 11

Ram wants to go to a trip with his friends, so he has packed three shirts and two pants with him. He thinks that if he has put on a different shirt and a different pant, then a new pair is formed and he can wear different pairs on different days. Now the question arises…