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求证1+sin2x-cos2x/1+sin2x+cos2x=tanx
人气:470 ℃ 时间:2019-10-01 09:27:51
解答
1+sin2x-cos2x
=1+2sinxcosx-1+2sinx^2
=2sinx(cosx+sinx)
1+sin2x+cos2x
=1+2sinxcosx+2cosx^2-1
=2cosx(cosx+sinx)
所以原式=sinx/cosx=tanx
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