, . n = 0,1,2...

. . Pn (a,b)() :



. . [-1,1] (1-)a (1 + )b (. ). . ( 1859). . . ( a = b = 0), ( a = b =-1/2) ( a = b = 1/2), ( a = b). . . . = Pn (a,b)():
? .

: