1+sec(x)/1-sec2(x)=cos(x)/cos(x)-1帮忙求左边=右边

问题描述:

1+sec(x)/1-sec2(x)=cos(x)/cos(x)-1
帮忙求左边=右边

好像是错题,最后推出2cos(x)平方=2cos(x)平方减1

左边=(1+1/cosx)/(1-1/cosx^2)
=(cosx^2+cosx)/(cosx^2-1)
=[cosx(cosx+1)]/[(cosx-1)(cosx+1)]
=cosx/(cosx-1)