= f () ( f ()), δ .
(.. ) (.. ).
1. .
, = . , = - f () , . , - f (x).
, =, y = f (x) . = .
2. .
y=f (x) ,
y = kx + b
k b
k = , b = (1)
, y = kx + b f (x), k b . , , y = kx + b f (x). , . + ¥ ( ) - ¥ ( ). .
= b ( k = 0) . (,f ()) : , = f () ¥, ¥, = f () b ¥, = f () ¥.