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(sinx+cosx)/(sinx-cosx)=3 求sin^2(x)+sinxcosx
人气:246 ℃ 时间:2020-05-17 09:05:14
解答
sinx+cosx=3sinx-3cosx
2sinx=4cosx
tanx=2
cosx^2=1/(1+tanx^2)=1/5
sinx^2=1-cosx^2=4/5
sinxcosx=tanxcosx^2=2/5
sinx^2+sinxcosx=4/5+2/5=6/5
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