sin (40°) + cos(40°) = sqrt ( 1 + sin x) square both sides
sin^2(40°) + 2sin(40°)cos(40°) + cos^2 (40°) = 1 + sin x
sin^2 (40°) + cos^2((40°) + 2sin(40°)cos(40°) = 1 + sin x
(1) + 2sin(40°)cos(40°) = 1 + sin x
2sin(40°)cos(40°) = sin x
sin ( 80°) = sin x
x = 80°
