2ln|sec X+tan X|=ln|(1+sin x)/(sin x-1)|怎么证
问题描述:
2ln|sec X+tan X|=ln|(1+sin x)/(sin x-1)|怎么证
答
2ln|secX +tanX|=2ln|1/cosX +sinX/cosX|=2ln|(1+sinX)/cosX|=ln|(1+sinX)²/cos²X|而cos²X=1-sin²X所以2ln|secX +tanX|=ln|(1+sinX)²/cos²X|=ln|(1+sinX)²/(1-sin²X)|=ln|(...