已知sinα+cosα=3/4,那么sin^3α-cos^3α的值为
人气：329 ℃ 时间：2020-04-06 09:40:21
解答
sinα+cosα=3/4,平方得：1+2 sinαcosα=9/16.sinαcosα=-7/32.则( sinα-cosα) ²=1-2 sinαcosα=23/16.∴sinα-cosα=±√23/4.sin^3α-cos^3α=( sinα-cosα)( sin²α+ sinαcosα+ cos²α) ...
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