Question

1-tgx/1+tgx
рЕБЯТ ПОМОГИТЕ

Answer 1

$frac{1-tgx}{1+tgx} = frac{1- frac{Sinx}{Cosx} }{1+ frac{Sinx}{Cosx} }= frac{ frac{Cosx-Sinx}{Cosx} }{ frac{Cosx+Sinx}{Cosx} } = frac{Cosx-Sinx}{Cosx+Sinx}$