Answer:
Ā y =CāeĖ£ + Cāeā»Ė£ Ā + Cā cos x + Cā sin x
Step-by-step explanation:
given,
yā½ā“ā¾ - y = 0
( Dā“ - 1 ) y = 0..............(1)
writing characteristics equation
mā“ -1 Ā = Ā 0
(m² - 1)(m² +1) = 0
(m - 1)(m+1)(m²+1) = 0
hence, roots of the equation comes out to be
       = 1, -1, ± i
so the general solution will be
Ā y =CāeĖ£ + Cāeā»Ė£ Ā + Cā cos x + Cā sin x