→ sugar317 :大大x-8怎麼一下分解成那些呢 05/05 01:01
→ Honor1984 :a^3 - b^3 = (a - b)(a^2 + ab + b^2) 05/05 01:04
→ sugar317 :原來如此 謝謝你 05/05 01:06
※ 引述《sugar317 (shadow)》之銘言：
: http://ppt.cc/6ez5
: 各位可以教我如何因式分解嗎
: 因為分母都為0
(x - 8) [x^(1/3) - 2][x^(2/3) + 2x^(1/3) + 4]
------------- = --------------------------------------
[x^(1/3) - 2] [x^(1/3) - 2]
可以約
因為x =/= 8
= x^(2/3) + 2x^(1/3) + 4
取極限後
= 4 + 2 * 2 + 4 = 12
1 1
----[ ---------- - 1 ]
x sqrt(x + 1)
1 1 - sqrt(x + 1)
= ----[ -----------------]
x sqrt(x + 1)
1 - x
= ----[ --------------------------------- ]
x sqrt(x + 1)[1 + sqrt(x + 1)]
x =/= 0
-1
= -----------------------------
sqrt(x + 1)[1 + sqrt(x + 1)]
取極限後
-1
= ---------------------
1 (1 + 1)
= -1/2
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