pure maths-有關proof既問題

相信以下係一正確用pure maths知識的做法
let f(x) = x4 - 3x2 + k
f'(x) = 4x3 - 6x
If a = b
therefore f(x) has repeat root
and a + a = 2
a = 1
that means f(1) = f'(1) = 0 if 1 is the repeat root of f(x)
but f'(1) = 4(1)3 - 6(1)
= -2 , which is not equal to 0
so , it make contradiction
therefore , a = b is wrong!
so , a is not equal to b

這題不難的，不過有點煩，就是這樣做。

圖片參考：http://i187.photobucket.com/albums/x22/cshung/7008090702609.png


2008-09-08 21:52:46 補充：
好吧，你的答案比較簡單，其實可行就可以啦～

2008-09-08 21:53:24 補充：
正確用pure maths知識的做法．．．．

正確既做法就係prove到就得。