. ' =F(X,Y).
. , F(x,y,y',, y(n) = 0, F(t0,t1,t2,, tn+1) , D R n+2, , , ',, (n) - .
. , .
f(x) (; b ), (;b) : F(x,f(x),f'(x),..., f(n)(x)) = 0. .
: ' =f(x,y). , '. ( "" , ' , F(x,y,y') = 0, ', ). .
( ). - D R2, - D. :
, , 1 y2, (a1;b1) (a2;b2), x0, , (;b) .
. , y1(x) (a1;b1) 2() (a2;b2), (a2;b2) (a1;b1) 1() ≡ 2() (a2;b2). , () D, () , D.
, () .
. ' =f(x,y) ' - (, ), f(x,y) f(x,y) . , D, .. (,) D , .
, (.) D . , .