規(guī)律如下:
y = 0 * (x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9) / (1-2)(1-3)(1-4)(1-5)(1-6)(1-7)(1-8)(1-9)
+ 2 * (x-1)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9) / (2-1)(2-3)(2-4)(2-5)(2-6)(2-7)(2-8)(2-9)
+ 7 * (x-1)(x-2)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9) / (3-1)(3-2)(3-4)(3-5)(3-6)(3-7)(3-8)(3-9)
+ 21 * (x-1)(x-2)(x-3)(x-5)(x-6)(x-7)(x-8)(x-9) / (4-1)(4-2)(4-3)(4-5)(4-6)(4-7)(4-8)(4-9)
+ 42 * (x-1)(x-2)(x-3)(x-4)(x-6)(x-7)(x-8)(x-9) / (5-1)(5-2)(5-3)(5-4)(5-6)(5-7)(5-8)(5-9)
+ 73 * (x-1)(x-2)(x-3)(x-4)(x-5)(x-7)(x-8)(x-9) / (6-1)(6-2)(6-3)(6-4)(6-5)(6-7)(6-8)(6-9)
+ 113 * (x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-8)(x-9) / (7-1)(7-2)(7-3)(7-4)(7-5)(7-6)(7-8)(7-9)
+ 163 * (x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-9) / (8-1)(8-2)(8-3)(8-4)(8-5)(8-6)(8-7)(8-9)
+ 221 * (x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8) / (9-1)(9-2)(9-3)(9-4)(9-5)(9-6)(9-7)(9-8)