求sin8/π是多少 sin8/兀等于多少

sin\u03c0/8=?

cos(\u03c0/4)=1-2sin²(\u03c0/8)
2sin²(\u03c0/8)=1-cos(\u03c0/4)
sin(\u03c0/8)=\u221a{[1-cos(\u03c0/4)]/2}
=\u221a[(1-\u221a2/2)/2]
=\u221a[(2-\u221a2)/4]
=[\u221a(2-\u221a2)]/2

sin8/\u5140\u7b49\u4e8e\u591a\u5c11
\u5e94\u8be5\u662f\uff1a
sin8\u5206\u4e4b\u03c0\u5427
sin8\u5206\u4e4b\u03c0
=[\u221a(2-\u221a2)]/2

sinπ/4展开就算sinπ/8=[√(2-√2)]/2

sin8/π= 0.31492251087768

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