ANSWERS 623
Section 12.8. Multiplication and D ivis io n b y t: page 561
1. [, (te-2t) = (s.1 2 )2.
3. .C (tsin3t) = (• 2 6.;. 9 )"
5. .C ( t sinh t) = (• 2 ~ 1 )2.
.c(";^1 ) =ln.~ 1.
.C (t sinbt) = t/_:g,)2.
ll. .c- 1 (tn (:~1}•) = 2 (e'~cost)_
1 3. y(t ) = te- t + t^2 e-t.
15. y(t) = Ctet.
17. y(t) = Ct.
1 9. y(t) = 1 - t.
Sect ion 12.9. I n verting the Laplace Transform: page 570
- .c-^1 <.(:!h) = - 1 + 3e^1.
(^3) · .c-1( •(•+2)(4.2-6ss-- 12) 2) = 3 + 2e - 2t _ e2t ·
(^5) • .c-1( (s2• 2t2)(s+s±3 -1) 2 ) = e-2t + e' + 2te' ·
7. .c -^1 ( , 2 ~ 4 ) = ~sin 2t.
9. .c -^1 (•
3
+\' -•+^3 ) = - 3 + e' + e-^1 +cost +sint = - 3 + 2 cosh t + cost+ sint.
$ -·
11. .c-1(•
3
+~:~~-+^1 ) = - 1 + e^1 + e-^1 - cost + sin t = - 1 + 2cosh t - cost+sint.
3 .c- 1(•
(^3) +2s (^2) r.4•+2 ) t. 2t
- (s2+l)s2+4) =COS +Sill.
1 5. y(t) = e-t + e- t sin 2t.
1 7. y(t ) = e-^1 +cos 2t + sin 2t.
- y(t) = 1 + t.