作业帮(tan91*tan92*……*tan179)/(sin^21+sin^22+……+sin^289)=
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(tan91*tan92*……*tan179)/(sin^21+sin^22+……+sin^289)=
(tan91*tan92*……*tan179)/(sin^21+sin^22+……+sin^289)=
(tan91*tan92*……*tan179)/(sin^21+sin^22+……+sin^289)=
tan91*tan92*……*tan179=（-tan89°）*（-tan88°）*……*（-tan1°）=（-cot1°）*（-cot2°）*…*（-cot44°）*（-tan45°）*（cot44°）*…*（-tan1°）=-1
分母=sin^21°+sin^22°+……+sin^244°+sin^245°+cos^244°+……+cos^22°+cos^21° =89/2
所以 最终结果为 -2/89
(tan91*tan92*……*tan179)/(sin^21+sin^22+……+sin^289)
=[tan(180-89)*tan(180-88)*...*tan(180-1)]*(sin²1+sin²2+...+sin²45+cos²44+cos²43+...+cos²1)
=-(tan89*tan88*...*t...
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(tan91*tan92*……*tan179)/(sin^21+sin^22+……+sin^289)
=[tan(180-89)*tan(180-88)*...*tan(180-1)]*(sin²1+sin²2+...+sin²45+cos²44+cos²43+...+cos²1)
=-(tan89*tan88*...*tan1)*[(sin²1+cos²1)+(sin²2+cos²2)+...+(sin²44+cos²44)+sin²45]
=(cot1*cot2*..*cot44*tan45*tan44*..*tan1)*(44+1/2)
=[(cos1*tan1)*(cot2*tan2)*...*(cot44*tan44)*tan45]*(44.5)
=(1*1*...*1)*(44.5)
=44.5
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