求tan15° 怎么求?最好有答题过程还有图! - 知识问答

求tan15° 怎么求?最好有答题过程还有图!

2个回答

cos30 °= √¯3/2
cos15 °= √¯[(1 + cos30° )/2]
sin15° = √¯[(1 - cos30° )/2]
tan15° = sin15° /cos15°
= √¯[(1 - cos30° )/(1 + cos30° )]
= √¯[(2 - √¯3)/(2 + √¯3)]
= (2 - √¯3)

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