(tan X + sec X – 1) / (tan X – sec X + 1) = (1 + sin X) / (cox X)

问题描述:

(tan X + sec X – 1) / (tan X – sec X + 1) = (1 + sin X) / (cox X)

secX=1/cosx,tanx=sinx/cosx,通分后,便可得