Question

tanπ/12的具体数值，急！

Answer 1

tanπ/12
=tan30
=根号3/3

追问

tanπ/12=tan15

追答

？
什么意思？

追问

tanπ/12等于tan15，你回答的tan30=根号3/3

追答

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