[ATTACH=full]2222[/ATTACH]
tan(α + β)=7...........1) tan(α - β)=5................2) _____________________________ from 1) and 2) we have α + β=tan^-1(7).........1a) α - β=tan^-1(5).............2a) ___________________________add both α + β+α - β =tan^-1(7)+tan^-1(5) 2α =2.8023 α =2.8023/2 α =1.40115...(result in radians) α + β=tan^-1(7).........1a) , substitute α =1.40115 1.40115+ β=tan^-1(7) β=tan^-1(7)-1.40115 β=0.0277493...(result in radians) => tan(α)=tan(1.40115)=5.83796...(result in radians)