: , , , .. , , .. , . , , . , , , , R +. , 0 () .
, R + R + , ( ). , 5 5, 8,14 8,14 .. , Î R +, , R . , 0. R +, R {0} R. ,
R = R + R {0},
R + R {0} ( , ).
, , x R +, < y (, 6, 10, 10 6, .. 4). > , , ( ) (, 6, 2, (6 2), .. 4). , , , , .
, . , 0 .
x x, Î R +, , . , , ( x) = x. , (6) = 6. 0 , 0 = 0.
, x, | x |. ,
, |12| = 12; |9| = 9; |0| = 0.
Î R Î R +
y Î R +. , (; ). ,
(7; 2) 5, 5 7 2, (3; 8) 5, 5 3 8.
|
|
, . , 4 , (1; 5), (1,5; 5,5), (2; 6) .., 3 (4; 1). (10; 7), (29; 26) .. , ( 1; 1), ( 2; 2) . , , 1 = x 1+ 2 = x 2+ . x 1 + 2 = x 1 + (x 2+ ) = (x 1+ ) + x 2 = = y 1 + x 2. , y 1 = x 1 ( ) 2 = x 2 ( a), x 1 = y 1 + ( a), x 2 = 2 + ( a); x 1 + 2 = x 2 + y 1. = 0. ( 1; 1) ( 2; 2) , x 1 + y 2 = x 2 + y 1.
. R 2+ R +, .. (; ), Î R +, y Î R +. , ( 1; 1) ( 2; 2) (
( 1; 1) ~ ( 2; 2)), x 1 + y 2 = = x 2 + y 1. , ( 1; 1) ~ ( 2; 2) , , R + . . , < , , (; ), , > , , ( ) . , = , (; ) 0.
(; ) , ( ). , . . , .