[2(cosα)^2-1]/2tan(π/4-α)*[sin(π/4+α)]^2化简

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[2(cosα)^2-1]/2tan(π/4-α)*[sin(π/4+α)]^2化简

[2(cosα)^2-1]/2tan(π/4-α)*[sin(π/4+α)]^2化简
[2(cosα)^2-1]/2tan(π/4-α)*[sin(π/4+α)]^2化简

[2(cosα)^2-1]/2tan(π/4-α)*[sin(π/4+α)]^2化简
注释:此题有可能是书写错误,可能是后面的括号写掉了.
我想原题应该是[2(cosα)^2-1]/[2tan(π/4-α)*[sin(π/4+α)]^2]化简.
它的化简结果是1.解题过程如下:
[2(cosα)^2-1]/[2tan(π/4-α)*[sin(π/4+α)]^2]
=cos(2α)/2*(cos(π/4-α)/sin(π/4-α))*(2/(1-cos(π/2+2α))
=cos(2α)/2*(1+cos(π/2-2α)/sin(π/2-2α))*(2/(1+sin2α))
=(cos(2α)/(1+sin2α))*((1+sin2α)/cos(2α))
=1