Y16y64y0 y0 0 y01 y09SolutionIt is a linear homogeneous ode
Y\'\'\'+16y\'\'+64y\'=0, y(0) = 0, y\'(0)=1, y\'\'\'(0)=-9
Solution
It is a linear homogeneous ode with constant coefficients
So solution is fo the form
y=exp(kx)
Substituting gives
k^3+16k^2+64k=0
k(K+8)^2=0
k=0,k=-8
k=-8 is a repeated root
y=A+e^{-8x}(B+Cx)
y(0)=A+B=0
So, A=-B
y=-B+e^{-8x}(B+Cx)
y\'(x)=-8e^{-8x}(B+Cx)+e^{-8x}C
y\'(0)=-8B+C=1 , C=1+8B
y\'\'(x)=16e^{-8x}(4Cx+4B-C)
y\'\'(0)=16(4B-C)=-9
16(4B-1-8B)=-9
(4B+1)=9/16
4B=-7/16
B=-7/64
A=7/64
C=1+8B=1-7/8=1/8
C=1/8
