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问题: 高1数学题1

求tan20度+4sin20度要过程谢谢

解答:

解:tan20°+4sin20°
=sin20°/cos20°+4sin20°
=(sin20°+4sin20°cos20°)/cos20°
=(sin20°+2sin40°)/cos20°
=(sin40°+sin20°+sin40°)/cos20°
=(2sin30°cos10°+sin40°)/cos20°
=(sin80°+sin40°)/cos20°
=2sin60°cos20°/cos20°
=2×(√3)/2
=√3.