Consider the differential equation: $y^{(7)}-3y^{(6)}+4y^{(5)}-4y^{(4)}+3y^{(3)}-y^{(2)}=0.$ Roots

$of$ the equation ${}^7-3{}^6+4{}^5-4{}^4+3{}^3-{}^2=0$ are $0,0,1,1,1,i,-i.$ Write the

solution $of$ the above differential equation.