Arithmetics various set of numbers
Download 1.81 Mb. Pdf ko'rish
|
Inha-math-info-book
- Bu sahifa navigatsiya:
- HIGHEST COMMON DIVISOR (HCD)
- ALGEBRA
- Fractions Summation and difference of fractions
- Converting mixed fraction into improper fraction
- Purely periodic fraction
- Mixed periodic fractions
- Cauchy theorem
- Formula for compound radical
- Abridged multiplication formulas
- Equations Linear equation
3
VARIOUS SET OF NUMBERS
1,2,3,4,… are natural numbers (used for counting)
0,1,2,3,4,… are whole numbers
…-4,-3,-2,-1,0,1,2,3,4,… are integers
2,3,5,7,11,13,17,19,23,… are prime numbers (divisible by 1 and itself)
4,6,8,9,10,12,14,…are composite numbers (divisible by a number other than 1 and itself)
HCD of the numbers will be the product of common prime factors in smallest powers.
LCM of the numbers will be the product of common prime factors in largest powers. Example. Find HCD and LCM of numbers 270, 300, 315. 5 3 2 270
3
2 2 5 3 2 300 7 5 3 315
2
HCD= 5 3
LCM= 18900 7 5 3 2 2 3 2 If
k n k n n n a a a a a ... 3 2 1 3 2 1 , then
Number of divisors:
) 1 ( ...
) 1 ( ) 1 ( 2 1
n n n
4
Sum of divisors:
1 1
1 1 1 1 1 2 1 2 1 1 1 2 1
n k n n a a a a a a S k
) 0 ( ,
r r q p a Here a is divisible, p is divider, q is private, r is residue. Fractions Summation and difference of fractions with the same denominators b c a b c b a . with the different denominators bd bc ad d c b a .
Multiplication d b c a d c b a . Division c b d a c d b a d c b a : .
If
, then
d c b a . If c b d a , then
d c b a . 5
b c b a b c a .
For instance: 3 17 3 2 3 5 3 2 5 . Proportions If
d c b a : : , then the followings are true: 1)
; 2) qd pc nd mc qb pa nb ma ; 3)
d b d c b a ; 4) b a d b c a ; 5) Separation of a into direct proportional k n m : : parts: ; ; ; k k n m a n k n m a m k n m a
and into inverse proportional parts: ; 1 1 1 1 ; 1 1 1 1 ; 1 1 1 1 k k n m a n k n m a m k n m a
If n n b a b a b a ...
2 2 1 1 , then: 1) 1
2 1 2 1 ...
... b a b b b a a a n n ; 2) 1 1 2 2 1 1 2 2 1 1 ... ... b a m b m b m b m a m a m a n n n n . Here n m m m q p n m ,...
, , , , , 2 1 are real numbers. 6
Infinite decimal fraction, which, starting from a certain category, form a sequence by assigning the right one and the same number is called periodic and recurring number - its period.
If repetition begins with the first digit after the decimal point, then this fraction is called purely periodic. For example: 0,(3); 1,(21); 15,(06),… Handling purely periodic fractions into simple: Period of purely periodic fraction take as the numerator and as the denominator write digit 9 as many times as numbers in the period. Example: 999 124
2 124
, 2 Mixed periodic fractions
Periodic fraction in which the repetition does not begin immediately after the decimal point, called mixed periodic. For instance: 0,1(3); 2,01(43). Handling mixed periodic decimal into simple: To turn a mixed periodic fraction into a simple it is sufficient to take the difference of number of standing up to the second period with the number, prior to the first period, and take as numerator, and in the denominator write digit 9 as many times as number of digits in a period, with as many zeros as numbers between the comma and the period. For instance: 99000
2015 2 99000 020 02035
2 ) 35 ( 020
, 2 . Average means If
n x x x ,...,
, 2 1 are given numbers, then the followings are true: 1)
The arithmetic mean: n x x x A n ... 2 1 ; 2) The geometric mean: n n x x x G ... 2 1 ; 7
3) The harmonic mean: n x x x n H 1 1 1 ...
2 1 ; 4)
The mean square: n x x x K n 2 2 2 2 1 ... ; 5) Weighted average: n n n a a a x a x a x a V ... ... 2 1 2 2 1 1 .
A G H . Percentage Finding р percent of a number а
% 100
a
% p x , 100 p a x Finding number а by the given percentage р % p a
% 100
x , p a x 100
The percentage of numbers а and b % 100
b a
Compound interest: n p a 100
1 ,
a is sum, p is percent, n is time. Properties of powers
8
1) q p q p a a a ; 2)
q p q p a a a : ;
3)
q p q p a a ; 4) p p p b a b a ;
5) p p p b a b a . Здесь 0 , 0
a .
N k k n a N k n a a n n
, 1 2 , k , 2 ,
1) m n m n a a ; 2) m n mp np a a ; 3) p n a a a n p n p n , ; 4) mn m n a a ; 5)
mnp p np m n p c b a c b a ; 6) 1 ...
n n n a a a a ;
7)
n n a a a a 2 1 2 ...
; 8)
1 ...
: : n n n n a a a a ;
9) 2 4 1 1 ... a a a a .
9
A m m A m A B A 2 ; 2 2 .
1 17 2 1 8 9 8 9 2 1 2 17 81 9 2 17 81 9 17 9
Abridged multiplication formulas 1)
2 2 2 2 b ab a b a ; 2) 2 2 2 2 b ab a b a
3) b a b a b a 2 2 ; 4) 3 2 2 3 3 3 3 b ab b a a b a ; 5)
3 2 2 3 3 3 3 b ab b a a b a 6)
2 2 3 3
ab a b a b a ; 7)
2 2 3 3
ab a b a b a ; 8)
2 2 4 4 b a b a b a b a . Equations Linear equation General form: 0
b ax
1) a b x R b a , 0 is unique solution; 2) x b a 0 , 0 no solution; 3)
0 , 0 infinitely many solutions. Quadratic equation General form: 0 2
bx ax , 0 a . 0 4 2 ac b D has two different roots.
4 2
b D has two similar roots.
4 2
b D has not any real roots. 10
Factorization: ) )( ( 2 1 2 x x x x a c bx ax , where 2 1 , x x are roots of the equation. Expansion in complete square: a ac b a b x a c bx ax 4 4 2 2 2 2 . Formula for finding roots: a ac b b x 2 4 2 2 , 1 . Download 1.81 Mb. Do'stlaringiz bilan baham: |
ma'muriyatiga murojaat qiling