化简:cos^2x / ( cot(x/2)-tan(x/2) )

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化简:cos^2x/(cot(x/2)-tan(x/2))化简:cos^2x/(cot(x/2)-tan(x/2))化简:cos^2x/(cot(x/2)-tan(x/2))令a=x/2则x=2a原式

化简:cos^2x / ( cot(x/2)-tan(x/2) )
化简:cos^2x / ( cot(x/2)-tan(x/2) )

化简:cos^2x / ( cot(x/2)-tan(x/2) )
令a=x/2
则x=2a
原式= cos²2a/(cosa/sina-sina/cosa)
=cos²2a/[(cos²a-sin²a)/sinacosa]
=cos²2a/[cos2a/sinacosa]
=sinacosacos2a
=1/2*sin2acos2a
=1/4*sin4a
=1/4*sin2x

=cos²x(tan(x/2) / [ 1-tan²(x/2)] )
=cos²xtanx/2
=cosxsinx/2
=sin(2x)/4

sin(x/2)cos(x/2)cos(x)