(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

y'' -6y' + 9y = f(t)

f(t)=

0, 0<t<1

1, 1<t<3

0, t>3

2. Relevant equations

3. The attempt at a solution

Turning it to heaviside functions I get:

y'' -6y' + 9y = u_{1}- u_{3}

and I solve.

in the answers it should be:

y(t) = 2te^{t}+ u_{1}(1/9 - 1/9e^{3(t-1)}+ 1/3(t-1)e^{3(t-1)}).

where did u_{3}go in the answers? why doesn't it appear? the u_{1}I can get just like that, but I can't seem to figure out where the u_{3}went and why there is a 2te^{t}in there.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: DE using Laplace transform

**Physics Forums | Science Articles, Homework Help, Discussion**