已知2007sin(2a+b)=2009sin(b),求证:tan(a+b)=2008tan(a)
问题描述:
已知2007sin(2a+b)=2009sin(b),求证:tan(a+b)=2008tan(a)
答
2007sin(2a+b)=2009sin(b),2007sin(a+b +a)=2009sin(a+b -a),2007sin(a+b)cosa+2007cos(a+b)sina=2009sin(a+b)cosa-2009cos(a+b)sina4016cos(a+b)sina=2sin(a+b)cosa2008cos(a+b)sina=sin(a+b)cosatan(a+b)=2008tan(...