4(a-b)³ -12(b-a)²equal to 4(a-b)³+12(a-b)²????

2006-11-21 5:51 am
4(a-b)³ -12(b-a)²equal to 4(a-b)³+12(a-b)²????

回答 (3)

2006-11-21 8:32 pm
✔ 最佳答案
there is only one case that
4(a-b)³ -12(b-a)²equal to 4(a-b)³+12(a-b)²
because

if 4(a-b)³ -12(b-a)²equal to 4(a-b)³+12(a-b)²
then -12(b-a)² = 12(a-b)²
that implies

24(a-b)²=0 =>(a-b)²=0

we can see, (a-b)²=0 if and only if a=b
otherwise

4(a-b)³ -12(b-a)²≠ 4(a-b)³+12(a-b)²

2006-11-22 11:35:31 補充:
只有一種情況,會使4(a-b)³ -12(b-a)²equal to 4(a-b)³ 12(a-b)²如果 4(a-b)³ -12(b-a)²等於 4(a-b)³ 12(a-b)²意味著 -12(b-a)² = 12(a-b)²這暗示了24(a-b)²=0 =>(a-b)²=0我們可以看出, (a-b)²=0 只有 a=b否則4(a-b)³ -12(b-a)²≠ 4(a-b)³ 12(a-b)²
2006-11-21 6:34 am
L.H.S = 4(a-b)^3 -12(b-a)^2
= 4(a-b)^3 + 12(a-b)^2
= R.H.S ,,
參考: ME
2006-11-21 5:57 am
LHS =4(a-b)³ -12(b-a)²
=4(a-b)³ -12(b²-2ab+a²)
RHS= 4(a-b)³+12(a-b)²
=4(a-b)³+12(a²-2ab+b²)
≠4(a-b)³ -12(b²-2ab+a²)

so 4(a-b)³ -12(b-a)² is not equal to 4(a-b)³+12(a-b)²


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