tan2α+1/tan2α=2 则sinαcosα=
人气：152 ℃ 时间：2020-06-04 03:10:33
解答
tan2α+1/tan2α=2
sin(2α)/cos(2α)+cos(2α)/sin(2α)=2
1/[sin(2α)cos(2α)]=2
sin(4α)=1
4α=2kπ+π/2
2α=kπ+π/4
sinαcosα=sin(2α)/2=sin(kπ+π/4)/2=±√2/4
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