Exam Notifications
20 May

## 20 May 2020

## 6 May 2020

Concepts
06 May

## Prime Numbers

## Prime Numbers

###
__Definition of Prime Number__

Prime number is a number which has only two factors 1 and the number itself

Examples: 2 = 1×2, 3=1×3,5=1×5,7=1×7,....

etc.

⊹ 1 is neither a prime nor a composite number.

⊹ 2 is the smallest prime number.

⊹ Greatest two digits prime number is 97

⊹ Greatest two digits prime number is 97

### How many prime numbers from 1 to 100?

25 prime numbers from 1 to 100.

The prime numbers are

2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97

2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97

### How many prime numbers from 1 to 200?

46 prime numbers from 1 to 200The prime numbers are

2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,199

###
__Twin Primes Number__

Two prime numbers whose difference is 2 are called twin primes.

For examples 3 and 5 are twin primes numbers since difference between 5 and 3 is 2.

### How many pairs of twin primes numbers from 1 to 100 ?

8 pairs of twin primes from 1 to 100

The pairs of twin primes numbers are

(3,5);(5,7);(11,13);(17,19);(29,31);(41,43);(59,61);(71,73)

## 3 May 2020

Solutions
03 May

## Prove that sin^2(6x)-sin^2(4x)=sin2x sin10x

## Prove that sin^2(6x)-sin^2(4x)=sin2x sin10x

## 2 May 2020

## 18 Apr 2020

Solutions
18 April

## Ganit Prakash Class IX Bengali Solution

##
Ganit Prakash Class IX Bengali Solution/

WBBSE Class 9 math bengali solution

## 27 Feb 2020

Solutions
27 February

## If tanA=(2x-k)/ksqrt(3) and tanB=xsqrt(3)/(2k-x) then show that |B-A|=30 degree

##
**If tanA=(2x-k)/ksqrt(3) and tanB=xsqrt(3)/(2k-x) then show that |B-A|=30 degree**

Download the pdf click the link below

download here

Solutions
27 February

## If tanA=xsinB/(1-xcosB) and tanB=ysinA/(1-ycosA) then show that sinA/sinB=x/y

## If tanA=xsinB/(1-xcosB) and tanB=ysinA/(1-ycosA) then show that sinA/sinB=x/y

Download the pdf click the link below