递推公式 T)=2xT,()-T(x) T,=1 T=x 证明： a =cos-x x=cosa cos(n+1a+cos(n-1)a=2cosa cosna T(x)+T(x)=2xT (x)递推公式 ( ) ( ) ( ) T x T T x xT x T x n n n = = + = - - 1 0 1 1 1 2 证明： x 1 cos- a = x = cosa cos(n +1)a + cos(n -1)a = 2cosa cos na T (x) T (x) xT (x) n n n 2 +1 + -1 =