1+ tga\1+ctga , если cosa=12\15 , 3п\2 меньше a меньше 2п

[latex]sin \alpha =- \sqrt{1- \frac{144}{225} }=- \frac{9}{15} [/latex] [latex]tg \alpha = \frac{sin \alpha }{cos \alpha } =- \frac{9*15}{15*12} = - \frac{9}{12} =- \frac{3}{4} [/latex] [latex]ctg \alpha = \frac{1}{tg \alpha }=- \frac{4}{3} [/latex] [latex]1+ \frac{- \frac{3}{4} }{1- \frac{4}{3}} =1+ \frac{3*3}{4*1}=1+2.25=3.25 [/latex]