Polynomial

2012-04-23 6:37 am
As follows:

If f(2x - 1) is divisible by 2x, what is f(x) divisible by?

回答 (4)

2012-04-23 10:12 am
✔ 最佳答案
I am with the first floor, but should the step be like this?

f(2x - 1) = Q(x) * 2x ----(1)

Let u = 2x - 1
x = (u+1)/2

Change all the x into u in (1)
f(u) = Q[(u+1)/2] * 2[(u+1)/2]
f(u) = Q[(u+1)/2] * (u+1)

[Change the variable u back to x]
f(x) = Q[(x+1)/2] * (x+1)

So, f(x) is divisible by (x + 1)
參考: 經數學人 ronaldchik.blogspot.com
2012-04-24 5:53 am
TamT:
f(2x - 1) is divisible by 2x. Not f(2x + 1) is divisible by 2x.
2012-04-23 9:48 am
2012-04-23 8:05 am
f(2x - 1) = Q(x) * 2x

Let y = 2x - 1

f(y) = Q(2y - 1) * (y + 1)

So, f(x) is divisible by (y + 1)

2012-04-23 14:15:55 補充:
Sorry. f(x) is divisible by (x + 1)


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