Question

SinA _COSA =7/13 than sinA +cosA=?

Answer 1

sinA-cosA=7/13
squaring both side
sin^2A+cos^2A-2sinA.cosA=49/169
1-2sinA.cosA=49/169
2sinA.cosA=1-49/169=120/169-------(1)
now
sinA+cosA=Y let
squaring both side
sin^2A+cos^2+2sinA.cosA=Y^2
1+120/169=Y^2
Y=17/13
hence
sinA+cosA=17/13