证明:(1+tanα+1/cosα) / (1-tanθ+1/cosα )=(1+sinα) / cosα
问题描述:
证明:(1+tanα+1/cosα) / (1-tanθ+1/cosα )=(1+sinα) / cosα
答
(1+tanα+1/cosα)/(1-tanθ+1/cosα)=[(cosa+sina+1)/cosa]/[(cosa-sina+1)/cosa]=(1+sina+cosa)/(1-sina+cosa)∵(1-sina+cosa)(1+sina)-cosa(1+sina+cosa) =1-sin²a+cosa+sinacosa-cosa-sinacosa-cos²a ...