Expanding:

`f(t)=` `t^2 · u(t)` `-t^2 · u(t-2)` ` + 4 · u(t-2)`

`f(t)=` `t^2 · {u(t)` ` - u(t-2)}` ` + 4 · u(t-2)`

So our graph is as follows. It is a parabola before `t=2`, and then has constant value `4` thereafter.

12345-112345-1tf(t)Open image in a new page

Graph of `f(t)`.

Easy to understand math videos:
MathTutorDVD.com