1. Let p be a prime no. If p divides a²
. Then p divides a,where a is a
positive integer.
2. √2 is irrational
3. Let x be a rational no. Whose
decimal expansion terminates .
Then x can be expressed in the
form of p/q, where p &q are co
prime, the prime factorisation of q
is of the form 2ⁿ, 5 raise to power m
, where n,m are non- negative
integers.
4. Let x = p/q be a rational number
such that the prime factorisation of q
is of the form 2ⁿ, 5 raise to power m .
Where n, m are non - negative
integers. Then x has a decimal
expansion which terminates.
5. Let x =p/q be a rational number, such
that the prime factorisation of q is not
of the form of 2ⁿ5 raise to power m .
Where n, m are non - negative integers.
Then x has a decimal expansion which
is non - terminating repeating.
Euclid
Given positive integers are a, b. There
exist unique integers q and r.
Satisfying a= bq +r ; 0 5 r < b
Division algorithm.
Steps to obtain the HCF of
two positive integers. Say
c and d, with c > d.
Step 1- apply euclid
division lemma, to c and d,
c=dp +r.
Step 2- if r = zero, d is the
HCF of c and d. If r is not
equal to zero, apply euclid
division to d and r.
Step 3- continue the
process till the
remainder is zero.
Division lemma.
Fundamental theorem of airthematic
Every composite no. Can be expressed as a
product of primes, and this factorisation is
unique, apart from the order in which the
prime factors occur
Composite no. X=p₁*p₂*p₃..*p₄ where
p₁p₂..px are prime no.