- #1

- 101

- 8

## Homework Statement

We want to find the Laplace transform for

f(t): 0 for t≤2 and (t-2)

^{2}for t≥2

## Homework Equations

I know that Lap{u

_{c}f(t-c)} = e

^{-cs}Lap{f(t)}=e

^{-cs}F(s)

I rewrite f(t)=0+g(t) where g(t) = 0 for 0≤t<2 and (t-2)

^{2}for t≥2

so we can write f(t)=g(t)= u

_{2}(t)*(t-2)

^{2}

Lap{f(t)}= (e

^{-2s}/s) * Lap{(t-2)

^{2}}

## The Attempt at a Solution

The answer in my bok is 2*(e

^{-2s})/(s

^{3})

But Lap{(t-2)

^{2}} is (2/s

^{3}) - (4/s

^{2})+(4/s)

why ?!