所以△OAB面积的最大值为2+3 23.解: (1)
?a?b??a5?b5?a6?ab5?a5b?b6?a?b??33?2?2a3b3?aba4?b4???4?ab?a2?b2?2?4(2)因为
?a?b?3?a3?3a2b?3ab2?b3?2?3ab?a+b?
?2+3?a+b?24?a+b??2?3?a+b?34所以?a+b?3?8,因此a+b≤2.
2017年普通高等学校招生全国统一考试数学试题理(全国卷2,含答案)
所以△OAB面积的最大值为2+323.解:(1)?a?b??a5?b5?a6?ab5?a5b?b6?a?b??33?2?2a3b3?aba4?b4???4?ab?a2?b2?2?4(2)因为?a?b?3?a3?3a2b?3ab2?b3?2?3ab?a+b??2+3?a+b?24?a+b??2?3?a+b?34所以?a+b?3?8,因此a+b
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