Question

laplace transfer of sin(alpha*x)

Answer 1

oh man if u had troubles messing up last laplace this one will be even more messier solving it by deffinition of laplace since you will have to use partial integration like 2 times xD

Answer 2

.....yay.....how bout show that this is linear
L subscript (alpha f + bravo g) of (s) = alpha L + bravo L

Answer 3

i just realize i have an hour to turn this in lol

Answer 4

oh damn wait a sec

Answer 5

http://www.youtube.com/watch?v=gMcs6RF_LrQ
http://www.youtube.com/watch?v=-cApVwKR1Ps

there quick watch these will take u 30 min max to write it all down :D

Answer 6

why didn't i think of this lol

Answer 7

u should always check there are LOT of stuff that can help you at youtube

Answer 8

you have any shot cuts to any oth ethe other question
1-show that laplace transform is linear
2-find the laplace transform of f prime of t in terms of Ls and use that to fins cos ax
3- show laplace transform 0 to infinity f(u) du is 1/sL (s)

FML!!!!

Answer 9

http://www.youtube.com/watch?v=D7CP4WTQpBo

i belive this is what u need for 1 that laplace transform is linear operator

Answer 10

and about 2 and 3 i dont think i can find videos or smt like that quickly i am not even sure what i need to do there :\

Answer 11

for 2 i was told use integration by parts so 0 to infinity f prime of t e^(-st) at cos alpha*x, this one i guess goes along the sin one I'm doing

Answer 12

3- 1/s 0 to infinity f(t) e^(-st) dt

Answer 13

thats all i know

Answer 14

i dunno what they told u to do for the 2 one but if its to find the laplace like you did for sin(ax) then its pretty much similar if its not that i totaly got no idea what u need to do

Answer 15

thank =x for your help

Answer 16

still here?

Answer 17

yeah i couldnt open the question dunno why

Answer 18

correct me if I'm wrong, lap ace transform of sin ax = a/(s^2+a^2), also like the video showed, my question is, is the answer = prime, let me type exactly what the question says

Answer 19

find the laplace transform of f prime of t, in terms of L(s) and use this result to find the laplace transform of cos ax (hint: use integration by parts with dv= f prime of t dt) so we have integral from 0 to infinity of f prime e^(-st)

Answer 20

ok so it says to do this
\[\int\limits_{0}^{infinity}{f'(t)e^{-st}dt}\]
if i understood it rgith

Answer 21

yes to solve for cos ax, so since i already solve for sine, i just need to put it together

Answer 22

just don't know exactly what its asking, but i know it relates to the answer os Ls of sin

Answer 23

so it says use integration by parts with dv=f'(t)dt using that we would have :
\[\int\limits_{}^{}{dv}=\int\limits_{}^{}f'(t)dt\]
so we would have
v=f(t)

Answer 24

...ok....?

Answer 25

i have e^(-st) f(t) + integral of f(t) 1/se^(-st)

Answer 26

hum but i totaly got no idea what to do maybe u should post question for that so someone else might help you .. :\

Answer 27

ok