求证!(1 + cosx )/sinx = cot(x/2)1 + cosx------- = co

发布时间:2021-03-16 08:29:04

求证!(1 + cosx )/sinx = cot(x/2)1 + cosx------- = cot(x/2)sinx可否写清楚一点。gykwz

网友回答

1 + cosx =1+2(cosx/2)^2-1=2(cosx/2)^2
1 + cosx
------- = 2(cosx/2)^2/2sin(x/2)*cos(x/2 )=cot(x/2)
sinx
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