Специальные функции. Мицик М.Ф. - 18 стр.

UptoLike

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.

( )
xT
n


( )
xt;ψ
, 
( )
( )
n
n
n
txT
ttx
tx
xt
=
=
+
=
0
2
21
1
;ψ
(57)

( )
xt;ψ
   
1<t
, 
1x
   
021
2
+ txt
. , 
( )
xt;ψ

1<t

( )
1,1,
21
1
0
2
<=
+
=
xttxT
txt
xt
n
n
n
, (58)

( )
xT
n

u
x
cos
=
(59)

( )
=
+
=
+
=
+
utut
osut
tut
osut
txt
xt
22
2
22
sincos1
1
cos21
1
21
1
( )( )
( )
n
n
iuniun
iuiuiuiu
tee
etetetet
osut
=
+=
+
=
0
2
1
1
1
1
1
2
1
11
1
(60)
    (57) (60), 

( )
xT
n

( )
(
)
uneexT
iuniun
n
cos
2
1
=+=
. (61)
 (61) 
x
 (59), 

xnxT
n
arccoscos=
. (62)
  ,   (59),  
 (61):
( )
( )( )
(
)
(
)
(
)
(
)
(
)
.11
2
1
11
2
1
sincossincos
2
1
2
1
22
22
++=
=
++=
=++=+
nn
nn
nn
iuniun
xxxx
xixxix
uiuuiuee
                                                                           .

                                               Tn ( x )
                                                                         ψ (t ; x ) ,
                                          1 − tx        ∞
                          ψ (t ; x ) =               = ∑ Tn ( x ) t n                                     (57)
                                       1 − 2tx + t 2
                                                       n =0

                 ψ (t ; x )                                                             t < 1,            x ≤1
                                                      1 − 2 xt + t 2 ≠ 0 .                            ,
ψ (t ; x )                                             t <1
                     1− tx          ∞
                                 = ∑ Tn ( x ) t n ,                    t < 1, x ≤ 1 ,                     (58)
                  1 − 2t x + t 2
                                   n =0

                                                            Tn ( x )
                                                   x = cos u                                              (59)

   1− tx           1 − t osu                1 − t osu
               =                   =                              =
1 − 2 t x + t 2 1 − 2 t cos u + t 2 (1 − t cos u )2 + t 2 sin 2 u
     1 − t osu            1 1                                        1 ∞ −iun
(            )(
 1 − t e −iu 1 − t e iu
                        =    
                              )           +
                                              1
                          2  1 − t e −iu 1 − t e iu
                                                                                 (
                                                                      = ∑ e + e iun t n        )        (60)
                                                                       2 n=0
                                                                               (57)           (60),
                        Tn ( x )

                              Tn ( x ) =       (
                                           1 −iun
                                           2
                                                             )
                                             e + e iun = cos un .                                         (61)
                       (61)                       x             (59),

                                      Tn ( x ) = cos(n arccos x ) .                                       (62)
                                           ,                              (59),
                      (61):

             (
        1 −iun
        2
                        1
                        2
                                  )   (
           e + eiun = (cos u − i sin u ) + (cos u + i sin u ) =
                                        n                    n
                                                                                          )
          1
          2
                  (     2
                            n
                                       ) (
        =  x − i 1 − x + x + i 1 − x  =
                                        2
                                           n

                                             
                                                                 )
          1
          2
                  (       n
                                      ) (
        =  x − x 2 − 1 + x + x 2 − 1  .
                                         n

                                           
                                                             )