中二數學題

copimax

數學題，中二，姨甥問我！
polynomial 題目。
if A(x+1)(x-1)+B(x-1)+c(x-1)=2x, find A,B,c?

對不起我打錯了，正確為If A(x+1)(x-1)+B(x+1)+c(x-1)=2x
  

1234ats

First expand and simplify Left Hand Side, and see if he can get anything out of it.

copimax

原帖由 bigfoothk 於 13-11-13 發表
polynomial是中二嗎?朋友好像是1A課程.....為小朋友請私補更有用,數只取起(x-1)

中一至中三也有，不過深度不同！

1234ats

Answer is:
no solution.

LingChiBaBa

Expand the left side and compare the coefficient of x^2, x and constant.
You would get A is 0 and B,c are 1.

copimax

原帖由 LingChiBaBa 於 13-11-13 發表
Expand the left side and compare the coefficient of x^2, x and constant.
You would get A is 0 and B, ...

correct

copimax

原帖由 090211bb 於 13-11-13 發表
應該代入x=1找b，代x=-1找c再代x=0找a，此方法快很多

這是model answer,
good.
thanks