(1+sinx)/cosx=-1/3,则cox/(sin-1)=?

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(1+sinx)/cosx=-1/3,则cox/(sin-1)=?
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(1+sinx)/cosx=-1/3,则cox/(sin-1)=?
(1+sinx)/cosx=-1/3,则cox/(sin-1)=?

(1+sinx)/cosx=-1/3,则cox/(sin-1)=?
cosx/(sinx-1)
=-1/3*cosx/(sinx-1)*cosx/(1+sinx)
=-1/3*cos²x/(sin²x-1)
=-1/3*cos²x/(-cos²x)
=1/3


优先考虑:(1+sinx)*(sin-1)/cosx^2=-1(因为我观察到平方差公式,并联想到三角函数中平方关系)
将(1+sinx)/cosx=-1/3代入上式
易得:
cox/(sin-1)=1/3