Laplaceova transformace. - Katedra matematiky FEL ČVUT
Laplaceova transformace. - Katedra matematiky FEL ČVUT
Laplaceova transformace. - Katedra matematiky FEL ČVUT
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Odtud plyne, že<br />
F (p) = 1<br />
p 2 +1 (1 + e−pπ ),<br />
jestliže použijeme větu o translaci a vzorec sin t 1<br />
p2 +1 .<br />
<br />
1 − cos t,<br />
9. f(t) =<br />
0,<br />
0 ≤ t ≤ π,<br />
t > π.<br />
Je f(t) = (1 − cos t)[1(t) − 1(t − π)] =<br />
1(t) − 1(t − π) − cos t1(t) + cos [(t − π) + π]1(t − π) =<br />
1(t) − 1(t − π) − cos t1(t) − cos (t − π)1(t − π).<br />
Odtud plyne, že<br />
F (p) = 1<br />
p (1 − e−pπ ) − p<br />
p 2 +1 (1 + e−pπ ),<br />
jestliže použijeme větu o translaci a vzorec cos t p<br />
p 2 +1 .<br />
Neřešené úlohy na obraz impulsu.<br />
Určete obraz F (p) k danému impulsu f(t).<br />
1. f(t) =<br />
2. f(t) =<br />
3. f(t) =<br />
4. f(t) =<br />
5. f(t) =<br />
6. f(t) =<br />
7. f(t) =<br />
8. f(t) =<br />
9. f(t) =<br />
2, 0 ≤ t ≤ 1, [F (p) = 2<br />
p (1 − e−p )]<br />
0, 2 < t.<br />
<br />
0, 0 ≤ t ≤ 1, 1 [F (p) = p (e−p − e−3p )]<br />
1, 1 < t ≤ 3,<br />
0, t > 3.<br />
<br />
e−t , 0 ≤ t ≤ 2, [F (p) = 1<br />
p+1 (1 − e−2(p+1) )]<br />
0, t > 2.<br />
2t, 0 ≤ t ≤ 1, [F (p) = 2<br />
p 2 (1 − e −p )]<br />
2, t > 1.<br />
t, 0 ≤ t ≤ 1, [F (p) = 1<br />
p 2 (1 − e −p ) − 1<br />
p e−p ]<br />
0, t > 1.<br />
1, 0 ≤ t ≤ 1 [F (p) = 1<br />
p (1 − 2e−p + e −2p )]<br />
−1, 1 < t ≤ 2,<br />
0, t > 2.<br />
2t, 0 ≤ t ≤ 1, [F (p) = 1<br />
p 2 (2 − 3e −p + e −3p )]<br />
3 − t, 1 < t ≤ 3,<br />
0, t > 3.<br />
t, 0 ≤ t ≤ 1, [F (p) = 1<br />
p2 (1 − e−p − e−2p + e−3p )]<br />
1, 1 < t ≤ 2,<br />
3 − t, 2 < t ≤ 3,<br />
0, t > 3.<br />
<br />
sin t, 0 ≤ t ≤ π<br />
2<br />
0, t > π<br />
2 .<br />
1<br />
, [F (p) = p2 π<br />
(1 − pe−p 2 )]<br />
+1