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Cauchyä¸çå¼çå½¢å¼ååæ³å°±æ¯ï¼è®°ä¸¤åæ°åå«æ¯ai, biï¼åæ (âai^2) * (âbi^2) ⥠(âai * bi)^2.
æ们令 f(x) = â(ai + x * bi)^2 = (âbi^2) * x^2 + 2 * (âai * bi) * x + (âai^2)
åæ们ç¥éææ f(x) ⥠0.
ç¨äºæ¬¡å½æ°æ å®æ ¹æåªæä¸ä¸ªå®æ ¹çæ¡ä»¶ï¼å°±æ Î = 4 * (âai * bi)^2 - 4 * (âai^2) * (âbi^2) ⤠0.
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