Uporaba Chebyshevovega polinom T_n (x) = cosh (n (arc cosh (x))), x> = 1 in povratna relacija T_ (n + 2) (x) = 2xT_ (n + 1) (x) - T_n ( x), s tem, da T_0 (x) = 1 in T_1 (x) = x, kako porves to cosh (7 arc cosh (1.5)) = 421.5?

Uporaba Chebyshevovega polinom T_n (x) = cosh (n (arc cosh (x))), x> = 1 in povratna relacija T_ (n + 2) (x) = 2xT_ (n + 1) (x) - T_n ( x), s tem, da T_0 (x) = 1 in T_1 (x) = x, kako porves to cosh (7 arc cosh (1.5)) = 421.5?
Anonim

# T_0 (1.5) # ali na kratko, # T_0 = 1 #.

# T_1 = 1,5 #

# T_2 = 2 (1.5) (1.5) T_1-T_0 = 4.5-1 = 3.5 #, uporabo #T_n = 2xT_ (n-1) -T_ (n-2), n> = 2 #.

# T_3 = 3 (3.5) -1.5 = 9 #

# T_4 = 3 (9) -3.5 = 23.5 #

# T_5 = 3 (23,5) -9 = 61,5 #

# T_6 = 3 (61,5) -23,5 = 161 #

# T_7 = 3 (161) -61.5 = 421.5 #

Iz wiki Chebyshev Polinomi Tabela,.

# T_7 (x) = 64x ^ 7-112x ^ 5 + 56x ^ 3-7x