√3 cos40°+sin40°/sin40°co - 知识问答

√3 cos40°+sin40°/sin40°cos40°

1个回答

是(√3 cos40°+sin40°)/(sin40°cos40°)吧?
如果是的话：
(√3 cos40°+sin40°)/(sin40°cos40°)
=2{[(√3)/2]cos40°+(1/2)sin40°}/[(sin80°)/2]
=4(sin60°cos40°+cos60°sin40°)/sin80°
=4sin100°/sin80°
=4sin(90°+10°)/sin(90°-10°)
=4cos10°/cos10°
=4

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