求证!(1 + cosx )/sinx = cot(x/2)1 + cosx------- = cot(x/2)sinx可否写清楚_数学解答

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

人气：392 ℃　时间：2020-01-30 03:39:30

解答

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