1]已知x^3+3x+a，可被x-2整除，且a為常數，求a的值
2]若3x=A(x-1)(x+2)+B(x-2)(x+2)+C(x+1)(x-1)，求A,B和C的值
中四續多項式，數學，幫幫我，THANK^_^
2011-03-07 12:08 am
回答 (2)
2011-03-07 12:17 am
✔ 最佳答案
1 代 x = 2﹐2^3 + 3(2) + a = 0a = -14
2 3x = A(x - 1)(x + 2) + B(x - 2)(x + 2) + C(x + 1)(x - 1)
代x = 1 => 3 = B(-1)(3) => B = -1
代x = -2 => -6 = C(-1)(-3) => C = -2
代x = 0 => 0 = -2A - 4B - C => 2A = -4B - C = 6 = > A = 3
2011-03-07 12:12 am
city u computing maths
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