Jika sin 2x =1\5 ,Tentukan (sin x + cos x)

(sin x + cos x)² = 1 + 2 sin x cos x
(sin x + cos x)² = 1 + sin 2x
(sin x + cos x)² = 1 + 1/5
(sin x + cos x)² = 6/5
sin x + cos x = √(6/5) = (1/5)√30
atau
sin x + cos x = (-1/5)√30