Find the solution to initial value problem d2ydt220dydt100y0
Find the solution to initial value problem
d^2y/dt^2-20dy/dt+100y=0
y(0)=7, y\'(0)=9
Solution
It is a linear homogeneous recurrence
So we assume solution of the form
y=exp(kt)
Substituting gives
k^2-20k+100=0
k=10 ie repeated roots
So general solution is
y(t)=e^{10t}(A+Bt)
y(0)=A=7
y\'(t)=10e^{10t}(A+Bt)+Be^{10t}
y\'(0)=10A+B=9=70+B
B=-61
y(t)=e^{10t}(7-61t)
