求证:tan平方x+1/tan平方x=2(3+cos4x)/1-cos4x

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求证:tan平方x+1/tan平方x=2(3+cos4x)/1-cos4x
求证:tan平方x+1/tan平方x=2(3+cos4x)/1-cos4x

求证:tan平方x+1/tan平方x=2(3+cos4x)/1-cos4x
证: =tanx+1/tanx =sinx/cosx+cosx/sinx =[(sinx)^4+(cosx)^4]/(sinxcosx) ={[(sinx)+(cosx)]-2(sinxcosx)}/(sinxcosx) =[1-2(sinxcosx)]/(sinxcosx) =4[1-1/2(sin2x)]/(sin2x) =2[4-2(sin2x)]/(1-cos4x) =2(3+cos4x)/(1-cos4x) 得证,祝你学习进步!

证: =tanx+1/tanx =sinx/cosx+cosx/sinx =[(sinx)^4+(cosx)^4]/(sinxcosx) ={[(sinx)+(cosx)]-2(sinxcosx)}/(sinxcosx) =[1-2(sinxcosx)]/(sinxcosx) =4[1-1/2(sin2x)]/(sin2x) =2[4-2(sin2x)]/(1-cos4x) =2(3+cos4x)/(1-cos4x)